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Journal Open Access

Nanophotonics

Editor-in-Chief: Stefan Maier
Edited by: Dennis Couwenberg

Language: English

First published: February 1, 2012

Publication Frequency: 24 issues per year

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About this journal

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From 1 October 2025, the journal will transition to a new publisher. Please submit all manuscripts through the new submission site: https://submission.wiley.com/journal/NAP2 .

You can find more information on the new Journal Homepage.

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Nanophotonics covers recent international research results, specific developments in the field and novel applications and is published in partnership with Sciencewise. It belongs to the top journals in the field and publishes research articles, reviews (by invitation only), letters, and perspectives.

Aims and Scope

Nanophotonics focuses on the interaction of photons with nano-structures, such as carbon nano-tubes, nano metal particles, nano crystals, semiconductor nano dots, photonic crystals, tissue and DNA. The journal covers the latest developments for physicists, engineers and material scientists, working in fields related to:

Plasmonics: metallic nanostructures and their optical properties
Meta materials, fundamentals and applications
Nanophotonic concepts and devices for solar energy harvesting and conversion
Near-field optical microscopy
Nanowaveguides and devices
Nano Lasers
Nanostructures, nanoparticles, nanotubes, nanowires, nanofibers
Photonic crystals
Integrated silicon photonics
Semiconductor quantum dots
Quantum optics & Quantum information
Ultrafast and nonlinear pulse propagation in nano materials and structures
Light-matter interaction, optical manipulation techniques
Nano-biophotonics
Optofluidics
Optomechanics
System applications based on nanophotonic devices
Nanofabrication techniques, thin film processing, self-assembly

Your Benefits

As a Nanophotonics author, you will benefit from:

High impact and high quality – Nanophotonics authors are the leading researchers in the field
Fast, fair, and constructive peer review
A continuous publication model and quick online publication of accepted papers (two weeks from acceptance to publication)
No limitations on colour figures and word count in published articles
All published articles being freely available worldwide through Open Access
Extensive promotion of published articles to a global audience
Retaining copyright as all articles are published with a CC-BY license by default
Distribution of published articles to open access directories, such as DOAJ, and thousands of libraries worldwide
Secure archiving by De Gruyter and independent archiving service Portico, meaning your work will be permanently available

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Publication Metrics

Average time from submission to initial Editorial Manager assessment: 5 days
Average time from submission to final decision (all article types): 57 days
Average time from acceptance to publication: 13 days

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Photonics Innovation Award in honor of Federico Capasso

Created to honor the innovative contributions of Federico Capasso to the field of photonics, the Photonics Innovation Award is a new prize of €4,000 from the Nanophotonics journal.

The winners will be announced in June 2025.

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Early Career Award

Nanophotonics supports young scientists by organizing the annual Early Career Award. This prestigious award acknowledges four early career scientists every year for their accomplishments, giving them recognition for their outstanding work in the field of nanophotonics.

Nominations for the 2025 award open soon.

Visit the award webpage for more information on previous winners, application criteria, and how to submit your nomination.

This award is fully sponsored by Nanophotonics.

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Article Processing Charges

To sustain the production of our fully refereed open access journal, each article accepted for publication in Nanophotonics is subject to an article processing charge of 2,650. This fee is used to cover the costs of the peer review process, professional typesetting, and copyediting, as well as online hosting, long-term preservation and extensive promotion to potential readers.

Information regarding payment of these charges will be provided following article acceptance. Enquiries concerning article processing charges should be addressed to the Publishing Editor. More information can be found in the Article Processing Charges policy document.

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Publication Ethics and Editorial Policies

Information on De Gruyter's Publishing Ethics can be found here. For further information on publication ethics, please refer to COPE's guidelines.
Guidelines for Author and Ethics Statements can be found in the Submit tab or downloaded from the Supplementary Materials below.

Open Access
Orthogonal canalized polaritons via coupling graphene plasmon and phonon polaritons of hBN metasurface

November 3, 2025

Chia-Chien Huang

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Metasurfaces composed of van der Waals materials exhibit extreme anisotropy and strong subwavelength confinement, enabling precise control of mid-infrared and terahertz waves for advanced photonic and optoelectronic applications. Among their intriguing phenomena, canalization – characterized by nearly diffraction-free propagation – offers significant potential for nanoscale light manipulation and enhanced light–matter interactions. Recently, gratings were demonstrated to induce synthetic transverse optical (STO) resonances, facilitating canalization perpendicular to the ribbon axis. In this study, we introduce a novel canalization mechanism by sandwiching a grating of hBN ribbons between graphene layers. The hybrid structure achieves orthogonal redirection of STO-induced canalization through the coupling plasmon polaritons in graphene and phonon polaritons in the hBN ribbons, achieving beam widths of approximately 300 nm (∼ λ 0 /20, where λ 0 is the free-space wavelength) across the spectral range of 1,470–1,510 cm −1 . Detailed analyses were conducted by varying graphene’s Fermi energy and geometric parameters, elucidating key field characteristics and spatial evolution of the canalization. Moreover, practical feasibility is demonstrated through simulated experimental antenna-launched excitation. Our finding holds promise for the development of polariton canalizations in diverse vdW material systems and facilitating on-chip photonic applications.
Open Access
Meso-chiral optical properties of plasmonic nanoparticles: uncovering hidden chirality

October 24, 2025

Yuanyang Xie, Alexey V. Krasavin, Anatoly V. Zayats

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Molecular chirality plays an important role in chemistry and biology, allows control of biological interactions, affects drug efficacy and safety, and promotes synthesis of new materials. In general, chirality manifests itself in optical activity (circular dichroism and/or circular birefringence). Chiral plasmonic nanoparticles have been recently developed for molecular enantiomer separation, chiral sensing and chiral photocatalysis. Here, we show that optical chirality of plasmonic nanoparticles exhibiting strong scattering can remain completely undetected using standard characterisation techniques, such as circular dichroism measurements. This phenomenon, which we term meso-chiral in analogy to meso-compounds in chemistry, is based on mutual cancellation of absorption and scattering chiral responses. As a prominent example, the meso-chiral behaviour has been numerically demonstrated in multi-wound-SiO 2 /Au nanoparticles over the entire visible spectral range and in other prototypical chiral nanoparticles in narrower spectral ranges. The meso-chiral property has been experimentally verified by demonstrating chiral absorption of gold helicoid nanoparticles at the wavelength where conventional circular dichroism measurements show absence of a chiral response. These findings demonstrate a valuable link between microscopic and macroscopic manifestations of chirality and can provide insights for interpreting a wide range of experimental results and designing chiral properties of plasmonic nanoparticles.
Open Access
Highly sensitive broadband photodetector based on PtSe₂ photothermal effect and fiber harmonic Vernier effect

October 29, 2025

Yinghui Gao, Yinping Miao, Xiaolan Li, Wangyang Nie, Yanxi Wang, Zhuoyang Han, Youlian Wang, Xuqi Wang, Rui Yang, Ran Wang, Jianquan Yao

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Platinum diselenide (PtSe 2 ), a two-dimensional material, has shown exceptional promise in photodetection applications because of its air stability, high carrier mobility, and layer-tunable bandgap. However, conventional photoconductive modes face challenges with high dark currents. To address this limitation, all-optical fiber detection technology with high sensitivity and response, has emerged as a promising approach for developing PtSe 2 , based devices. In this study, a high-sensitivity broadband photodetector based on PtSe 2 with a cascaded Fabry–Pérot interferometer (FPI) is proposed, which utilises the broad spectral absorption property of PtSe 2 and the interference enhancement mechanism of cascaded F–P cavities to achieve high-sensitivity broadband photodetection. The experimental results show that the detector has excellent spectral response in the 808–1,550 nm band, with a sensitivity of 3.867 nm/mW at 980 nm and a response time of 37.43 ms/129.17 ms. The sensitivity at 1,550 nm is up to 134.014 nm/mW, with a response time of 75.74 ms/28.66 ms. The double matching of 0.8 eV energy and PtSe 2 material, which is situated in the range of the material intrinsic absorption peak (1,200–1,600 nm), is responsible for the excellent sensitivity at 1,550 nm. It is also highly matched with the interband jump energy level, which generates more hot carriers per unit optical power and thereby increases the photothermal conversion efficiency. This study provides a new solution for the design of high-sensitivity, ultra-wideband optical fiber photodetectors, which has important potential applications in optical communications, environmental monitoring, and sensing.
Open Access
Tunable BIC metamaterials with Dirac semimetals

October 29, 2025

Xiaoyong He, Wenhan Cao, Fangting Lin

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Proposed by von Neuman and Wigner in 1929, bound states in the continuum (BIC) exhibit the merits of ultrahigh Q–factor and strongly confined modes, solving the inherent high dissipation of metamaterials (MMs) and plasmonic devices. Dirac semimetal (DSM) possesses the advantages of high carrier mobility and outstanding tunable properties, which provides avenues for the design of performance functional devices. This review focuses on recent progresses of the DSM (graphene and 3D Dirac semimetals, e.g. Cd 3 As 2 ) and other novel materials ( e.g. MoS 2 , borophene, GaSe) based BIC MMs, including the effects of Fermi levels, resonators types, and operation frequency ranges. Some related interesting phenomena, such as tunable Fano resonance, strong epsilon-nearly-zero and nonlinear harmonic effects, together with a brief prospect on the future development trends of DSM MMs, have been given and discussed. This work also provides a useful guideline to understand the tunable mechanism of the DSM devices and develop high performance functional devices applied in the fields of wireless communications, security detection, and sub-millimeter astronomical observations, e.g. filters, modulators and polarizers.
Open Access
Wafer-scale CMOS foundry silicon-on-insulator devices for integrated temporal pulse compression

November 5, 2025

Ju Won Choi, Kenny Y.K. Ong, Masaki Kato, Gemma Y.N. Chee, Benjamin J. Eggleton, Radhakrishnan Nagarajan, Dawn T.H. Tan

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Optical pulses are essential as information carriers, for driving nonlinear light sources, imaging, the study of attosecond science and 3D printing. In many applications, short pulses are needed. For example, the resolution of imaging methods which utilize short pulses is limited by the temporal width of the pulses, as is the capacity of time division multiplexed data. The temporal compression of optical pulses is an important approach to achieving ultrashort pulses. With the widespread proliferation of silicon photonics and their use in a multitude of applications, an integrated, CMOS-compatible approach for pulse compression would allow its seamless integration with other photonic integrated circuits. In this work, we experimentally demonstrate silicon-based pulse compression fabricated in a CMOS foundry. The first technique utilizes two stages, one for generating self-phase modulation through the Kerr nonlinearity in silicon, and the second for temporal synchronization of the new wavelengths. The second technique leverages Bragg soliton-effect temporal compression. We experimentally demonstrate temporal compression of up to 3.6× and good agreement with numerical calculations. This work represents efficient silicon-on-insulator devices for temporal compression realized using a wafer-scale CMOS foundry process and may therefore be mass manufactured and integrated seamlessly with other photonic and electronic circuits.
Open Access
Multi-channel and free-spectral-range-free tunable add-drop filters on thin-film lithium niobate

October 28, 2025

Ziliang Ruan, Xijie Wang, Bin Chen, Gengxin Chen, Liu Liu

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Thin-film lithium niobate (TFLN) has emerged as an attractive platform for integrated tunable photonic filters owing to its strong electro-optic response and low optical loss. However, conventional resonant filters, such as micro-rings, are intrinsically constrained by a limited free spectral range (FSR), which hinders their use in broadband and multi-channel operations. Here we present a TFLN-based add-drop filter that overcomes this limitation by employing a side-coupled travelling-wave Fabry–Pérot (FP) cavity formed with asymmetric multimode waveguide gratings (AMWGs). By engineering the inter-modal coupling through waveguide width tailoring and the reflection bandwidth of AMWGs, we realize a cavity with an intrinsic quality factor of 2.5 × 10 5 . The add-drop filter device also exhibits an FSR-free response across 1,500–1,630 nm wavelength band. A single resonance with a through-port extinction ratio of 20.23 dB and a drop-port insertion loss of 1.81 dB. Wavelength tuning by thermo-optic and electro-optic effect is demonstrated with efficiencies of 34.82 pm/K and 6.9 pm/V, respectively. Furthermore, a four-channel add-drop filter array with 3.2 nm channel spacing and 1.35 dB total through-port insertion loss validates the scalability of the present device. This work demonstrates an efficient approach to overcome the FSR constraint of sharp wavelength filters on TFLN. It can be potentially adopted in dense-wavelength-division-multiplexing communication systems, narrow-bandwidth microwave photonic filters, or high-resolution spectrometers.
Open Access
Robust transport of high-speed data in a topological valley Hall insulator

November 13, 2025

Byoung-Uk Sohn, George F. R. Chen, Hongwei Gao, Doris K. T. Ng, Dawn T. H. Tan

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Photonic topological insulators provide robust transport of light, enabling interesting phenomena such as unidirectional light propagation and immunity to disorder. The discovery of how to effectively break time reversal symmetry was an important development in the field of photonic topological insulators. Knowledge on how to implement designs in all-dielectric systems was an especially crucial development, enabling complementary metal-oxide semiconductor-based materials and processes to be used to study such structures, accelerating their pace of innovation. On the other hand, transmission of high-speed data is of fundamental importance in communications systems prolific in data centers and telecommunications. In this paper, we demonstrate robust transport of high-speed non-return-to-zero (NRZ) and pulse amplitude modulation 4 (PAM4) in a photonic topological insulator based on the quantum valley Hall effect. The structure utilizes a Kagome lattice with a slightly broken symmetry to achieve a domain wall between two regions with half-integer valley Chern numbers. The topological structure’s immunity to backscattering allows high-speed data to be transmission through a zigzag path with four 120° bends. Characterization of reference devices including a trivial device and photonic waveguide device shows that the topological device is superior in the robust transport of high-speed data, enabling a low BER of 10 −8 for 30 Gbps NRZ data and an open eye observed for 100 Gbps PAM4 data even when transmitted through a zigzag optical path.
Open Access
Nature inspired design methodology for a wide field of view achromatic metalens

October 13, 2025

Jacob Engelberg, Ronen Mazurski, Uriel Levy

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Metalenses have become ubiquitous in academic research and have begun to make their transition to industry. However, chromatic aberration still greatly limits the applications of metalenses. Achieving a wide field-of-view (FOV) is another challenge that has been dealt with successfully by using a removed stop, but when combined with a broadband spectrum, lateral chromatic aberration severely limits performance. In this paper, we tackle this challenge and present a comprehensive design methodology for a simultaneously wide-FOV and achromatic metalens, which is inspired by the human visual system. As a design example, we present a metalens operating in the near infrared (NIR), with 10 % relative spectral bandwidth (807–893 nm), focal length of 5 mm, F/5, and FOV of ±20°. In particular, we show how to optimize the stop position and correct the lateral chromatic aberration, both of which have not been reported in the past. In addition, we evaluate the performance of the metalens using accurate performance metrics and demonstrate the improvement compared to a chromatic metalens. Our approach paves the way for the design of wide FOV metalenses that can operate over a relatively large bandwidth, effectively contributing to the widespread implementation of metalens science and technology.
Open Access
MCP-enabled LLM for meta-optics inverse design: leveraging differentiable solver without LLM expertise

December 4, 2025

Yi Huang, Bowen Zheng, Yunxi Dong, Hong Tang, Huan Zhao, Rakibul Hasan Shawon, Sensong An, Hualiang Zhang

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Automatic differentiation (AD) enables powerful metasurface inverse design but requires extensive theoretical and programming expertise. We present a Model Context Protocol (MCP) assisted framework that allows researchers to conduct inverse design with differentiable solvers through large language models (LLMs). Since LLMs inherently lack knowledge of specialized solvers, our proposed solution provides dynamic access to verified code templates and comprehensive documentation through dedicated servers. The LLM autonomously accesses these resources to generate complete inverse design codes without prescribed coordination rules. Evaluation on the Huygens meta-atom design task with the differentiable TorchRDIT solver shows that while both natural language and structured prompting strategies achieve high success rates, structured prompting significantly outperforms in design quality, workflow efficiency, computational cost, and error reduction. The minimalist server design, using only 5 APIs, demonstrates how MCP makes sophisticated computational tools accessible to researchers without programming expertise, offering a generalizable integration solution for other scientific tasks.
Open Access
Bridging the scalability gap in van der Waals light guiding with high refractive index MoTe₂

December 8, 2025

Mikhail K. Tatmyshevskiy, Georgy A. Ermolaev, Dmitriy V. Grudinin, Aleksandr S. Slavich, Nikolay V. Pak, Marwa A. El-Sayed, Alexander Melentev, Elena Zhukova, Roman I. Romanov, Dmitry I. Yakubovsky, Andrey A. Vyshnevyy, Sergey M. Novikov, Aleksey V. Arsenin, Valentyn S. Volkov

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van der Waals transition metal dichalcogenides, distinguished by a high refractive index and giant optical anisotropy, are promising materials for integrated photonic devices. However, their superior optical properties are nowadays limited to exfoliated samples with only a micrometer scale, whereas industrial integration requires at least cm-scale dimensions. Here, we resolve this problem for MoTe 2 by demonstrating that chemical vapor deposition synthesis can provide an identical optical response to the benchmark exfoliated samples in a broad spectral range (250–5,000 nm). It allows us to show high-performance waveguiding properties of MoTe 2 with a subwavelength footprint of ∼ λ /8 for telecommunication wavelengths. Therefore, our findings reveal MoTe 2 as an ideal platform for the next-generation nanophotonics.
Open Access
High external power narrow bandwidth erbium doped waveguide laser on thin film lithium niobate

November 3, 2025

Yu Ma, Mengqi Li, Jianping Yu, Zhiwei Fang, Min Wang, Jintian Lin, Haisu Zhang, Ya Cheng

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Erbium-doped waveguide lasers have attracted great interests in recent years due to their compact footprint, high scalability and low phase noise. In this work, by using a high-external-gain erbium-doped thin-film lithium niobate waveguide as the gain medium, a fiber-Bragg-grating based Fabry–Perot-type laser is demonstrated with the low pump threshold of few-milliwatts, narrow bandwidth of 0.1 nm, high external output power above 2 mW and maximum optical signal-to-noise ratios above 50 dB. Laser linewidth measurements by self-delayed homodyne and heterodyne detections reveal the underlying multi-longitudinal-mode laser structure and the average intrinsic linewidth as low as ∼50 kHz for the individual longitudinal-modes. Theoretical modeling of the waveguide laser is also conducted with high consistence with the experimental measurements. The demonstrated high-power erbium-doped waveguide laser on thin-film lithium niobate can find diverse applications in optical communication and laser sensing.
Open Access
Optimizing the localization precision in coherent scattering microscopy using structured light

November 7, 2025

Ulrich Hohenester, Felix Hitzelhammer, Georg Krainer, Peter Banzer, Thomas Juffmann

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We employ the concept of quantum Fisher information to optimize the focused excitation fields in coherent scattering microscopy. Our optimization goal is to achieve the best possible localization precision for small scatterers located above a glass coverslip, while keeping the intensity of the total incoming excitation fields fixed. For small numerical aperture (NA) values, the optimal fields have linear or circular polarization, and the excitation beam can be well approximated by a Gaussian one. For larger NA values, the optimal beam acquires radial polarization. We show that the high localization precision can be attributed to high field strengths at the scatterer position, and correspondingly a large number of scattered and detected photons. Finally, we evaluate the performance of the optimized beams in interferometric scattering microscopy (i scat ), and further optimize these fields for i scat localization using the concept of Fisher information.
Open Access
Cavity-mediated coupling between local and nonlocal modes in Landau polaritons

November 18, 2025

Sae R. Endo, Dasom Kim, Shuang Liang, Geon Lee, Sunghwan Kim, Alan Covarrubias-Morales, Minah Seo, Michael J. Manfra, Dukhyung Lee, Motoaki Bamba, Junichiro Kono

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The multimode ultrastrong coupling (USC) regime has emerged as a novel platform for accessing previously inaccessible phenomena in cavity quantum electrodynamics. Of particular interest are cavity-mediated correlations between local and nonlocal excitations, or equivalently, between modes at zero and finite in-plane momentum, which offer new opportunities for controlling light–matter interactions across space. However, direct experimental evidence of such interactions has remained elusive. Here, we demonstrate nonlocal multimode coupling in a Landau polariton system, where cavity photons simultaneously interact with the zero-momentum cyclotron resonance and finite-momentum magnetoplasmons of GaAs two-dimensional electron gas. Our slot cavities, with their subwavelength mode volumes, supply in-plane momentum components that enable the excitation of finite-momentum matter modes. Terahertz time-domain magnetospectroscopy measurements reveal a clear splitting of the upper-polariton branch, arising from hybridization between magnetoplasmon modes and the cavity–cyclotron-resonance hybrids. Extracted coupling strengths confirm USC of the cyclotron resonance and strong coupling of the magnetoplasmon modes to the cavity field, respectively. The experimental results are well captured by the multimode Hopfield model and finite-element simulations. These findings establish a pathway for engineering multimode light–matter interactions involving zero- and finite-momentum matter modes in the USC regime.
Open Access
Second-harmonic generation in NbOI₂-integrated silicon nitride microdisk resonators

November 7, 2025

Ning Liu, Qiang Liu, Yutian Lin, Zhihong Zhu, Ken Liu

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In recent years, two-dimensional (2D) niobium oxide dihalides (e.g., NbOI 2 ) have garnered significant research interest in nonlinear photonics due to their prominent second-order nonlinear optical properties. Integrating these materials with high-quality-factor optical microcavities represents a crucial approach for developing high-performance on-chip nonlinear optical devices. This work demonstrates NbOI 2 -integrated silicon nitride (Si 3 N 4 ) microdisk resonators that achieve second-harmonic generation under low-power (sub-milliwatt) continuous-wave laser pumping, leveraging the superior second-order nonlinearity of NbOI 2 and the strong optical field confinement capability of Si 3 N 4 microdisks. The conversion efficiency of the device is calculated to be about 0.024 %/W. The intrinsic lack of inversion symmetry in NbOI 2 crystals avoids the laborious layer-number-dependent symmetry screening typically required for other 2D materials, while the developed van der Waals transfer technique provides a universal strategy for integrating niobium oxide dihalides with photonic microcavities. This study not only establishes a material-photon co-design strategy for on-chip nonlinear light sources but also lays a critical foundation for advancing quantum photonic chips and on-chip metrology systems.
Open Access
Ultrafast optical modulation of vibrational strong coupling in ReCl(CO)₃(2,2-bipyridine)

November 13, 2025

Liying Chen, Alexander M. McKillop, Ashley P. Fidler, Marissa L. Weichman

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Polaritons – hybrid light-matter states formed from the strong coupling of a bright molecular transition with a confined photonic mode – may offer new opportunities for optical control of molecular behavior. Vibrational strong coupling (VSC) has been reported to impact ground-state chemical reactivity, but its influence on electronic excited-state dynamics remains unexplored. Here, we take a first step towards excited-state VSC by demonstrating optical modulation of the ReCl(CO) 3 (bpy), (bpy = 2,2-bipyridine) complex under VSC using femtosecond ultraviolet (UV)-pump/infrared (IR)-probe spectroscopy. We establish ground-state VSC of ReCl(CO) 3 (bpy) in a microfluidic Fabry-Pérot cavity equipped with indium tin oxide (ITO)-coated mirrors. ITO is effectively dichroic as it is reflective in the IR and transmissive in the UV-visible and therefore minimizes optical interference. Excitation with UV pump light drives ReCl(CO) 3 (bpy) into a manifold of electronic excited states that subsequently undergo non-radiative relaxation dynamics. We probe the transient response of the strongly-coupled system in the mid-IR, observing both Rabi contraction and cavity-filtered excited-state absorption signatures. We reconstruct the intrinsic response of intracavity molecules from the transient cavity transmission spectra to enable quantitative comparison with extracavity control experiments. We report no changes in the excited-state dynamics of ReCl(CO) 3 (bpy) under ground-state VSC. However, we do observe significant amplification of transient vibrational signals due to classical cavity-enhanced optical effects. This effort lays the groundwork to pursue direct excited-state VSC aimed at modulating photochemical reactivity.
Open Access
From bound states to quantum spin models: chiral coherent dynamics in topological photonic rings

November 25, 2025

Fatemeh Davoodi

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Topological photonic systems offer a robust platform for guiding light in the presence of disorder, but their interplay with quantum emitters remains a frontier for realizing strongly correlated quantum states. Here, we explore a ring-shaped Su-Schrieffer-Heeger (SSH) photonic lattice interfaced with multiple quantum emitters to control topologically protected chiral quantum dynamics. Using a full microscopic model that includes cascaded Lindblad dynamics and chiral emitter-bath couplings, we reveal how the topology of the bath mediates nonreciprocal, long-range interactions between emitters. These interactions lead to rich many-body spin phenomena, including robust coherence, directional energy transfer, captured by an effective spin Hamiltonian derived from the system’s topology. We show that topological bound states enable unidirectional emission, protect coherence against dissipation, and imprint nontrivial entanglement and mutual information patterns among the emitters. In particular, we showed that under circularly polarized excitation, the emitters not only inherit spin angular momentum from the field but also serve as transducers that coherently launch the spin-orbit-coupled topological photonic modes into the far field. Our results establish a direct bridge between topological photonic baths and emergent quantum magnetism, positioning this architecture as a promising testbed for studying chiral quantum optics, topologically protected entangled states, and long-range quantum coherence.
Open Access
One-dimensional dielectric grating structure for plasmonic coupling and routing

December 5, 2025

Lam Yen Thi Nguyen, Yu-Cheng Lin, Tzu-Yu Chiu, Shao-Jin Liao, Chia-Chen Hsu, Jiunn-Yuan Lin, Hung-Chih Kan

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We propose and demonstrate one-dimensional (1-D) TiO 2 dielectric grating structures that couple 793-nm wavelength light and two-dimensional (2-D) surface plasmon polaritons (SPPs) into guided 1-D SPPs supported by dielectric-loaded plasmonic waveguides. The 1-D grating structure consists of a central TiO 2 stripe with a periodic array of TiO 2 teeth attached to the stripe. Finite-difference time-domain (FDTD) simulations reveal that the electromagnetic boundary conditions created by the teeth bend the electric field and induce charge oscillations under the grating, enabling excitation of SPPs. The same mechanism supports the routing of 2-D SPP. In the simulation the symmetric gratings achieve a maximum coupling efficiency of 19.1 % at an optimized grating period of Λ = 600 nm, and 1.7 % for asymmetric gratings. Both types exhibit strong polarization selectivity: symmetric gratings couple only under TM excitation, whereas asymmetric gratings respond under TE excitation. Experimental confirms these behaviors, yielding a coupling efficiency of ∼13 % for optimized symmetric gratings. The structures also function as SPP routers. Asymmetric gratings route incoming 2-D SPPs into 1-D TiO 2 waveguides with a simulated routing efficiency of 5.7 %, compared to 4.0 % for symmetric designs. The devices offer a ∼14 nm bandwidth around 793 nm and a small footprint of 18.7 μm 2 , resulting in a figure of merit (efficiency/area) of 0.71 % μm −2 , the highest among reported devices designed to couple free-space light directly into 1-D SPP waveguides. These results demonstrate that 1-D TiO 2 gratings offer a compact and multifunctional platform for efficient coupling and routing of SPPs in integrated plasmonic circuits.
Open Access
Ultranarrow polaritonic cavities formed by one-dimensional junctions of two-dimensional in-plane heterostructures

November 27, 2025

Seojoo Lee, Ji-Hun Kang

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We propose two-dimensional (2D) in-plane heterostructures, composed of a 2D crystal adjoining a perfect electric conductor (PEC) plane, that enable ultranarrow polaritonic resonant cavities. Specifically, we theoretically investigate the interaction of 2D surface polaritons (2DSPs) with the junction between the 2D crystal and a PEC plane. We reveal that when 2DSPs are strongly confined, the reflected 2DSPs experience a phase shift of 3 π /4, which exhibits π /2 deviation from the so-called edge reflection value. This non-trivial phase shift is shown to play a crucial role in enabling resonant cavities whose size can be far smaller than the wavelength of the 2DSPs. Furthermore, we demonstrate that the spatial dimensionality of our heterostructure allows a direct mapping to metasurface-based heterostructures, where the 2D crystal is replaced by a metasurface supporting spoof surface polaritons (SSPs). This correspondence extends the feasibility of our concept to SSP-based resonators and broadens the accessible frequency range into the terahertz and microwave regimes. Our work provides not only deeper insight into low-dimensional polariton optics but also a design strategy for ultracompact polaritonic metaresonators.
Open Access
Continuously tunable broadband adiabatic coupler for programmable photonic processors

November 6, 2025

Xiang Liu, Peipeng Xu, Yingxuan Zhao, Zhen Sheng, Fuwan Gan

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Programmable integrated photonic circuits are poised to drive a new revolution in information systems by synergizing with high-speed digital signals. Central to this vision is the ability to reconfigure optical signal processing for multi-functional photonic integration. Here, we design and experimentally demonstrate a thermo-optically reconfigurable adiabatic coupler monolithically integrated on a silicon photonics platform. The device combines adiabatic directional couplers with titanium nitride (TiN) micro-heaters embedded in the adiabatic transition region, enabling dynamic coupling ratio tuning via the localized thermo-optic modulation. Experimental results confirm continuous coupling ratio adjustment from 50:50 to 70:30 across 80-nm bandwidth (1,520–1,600 nm), with insertion loss kept below 0.25 dB. Leveraging its tunability, the device enables programmable spectral routing with free spectral ranges (FSR) of 20 nm and 40 nm. The proposed approach offers enhanced flexibility and scalability for high-density photonic systems, providing a promising pathway toward next-generation programmable photonic circuits and optical computing architectures.
Open Access
Deep-subwavelength resolution detection of polar magnetization by optical spin meron lattices on hyperbolic metamaterials

October 31, 2025

Jingya Wu, Weiyu Wei, Kefeng Guo, Xiangyang Xie, Aiping Yang, Xinrui Lei, Peng Shi, Qiwen Zhan, Xiaocong Yuan

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Magnetic-optical Kerr or Faraday effects have been widely used to measure magnetic domain structures by analyzing far-field polarization properties, with resolution limited by the wavelength scale of light. Here, we propose a methodology to measure the magnetic domain at a deep-subwavelength scale by investigating the interactions between a magnetic film and a topological meron spin lattice on the surface of hyperbolic metamaterials (HMMs), which support high- k modes. By introducing a grating structure on the HMM surface to excite volume plasmon polaritons, optical meron spin lattices are formed on the outer surface of the HMM. Subsequently, utilizing the spin–orbit couplings of the topological lattices in the presence of magnetization, a 0.158 λ resolution and 100 % high-precision detection of the magnetic domain structures with random polar orientations was achieved by altering the incident polarizations from right-handed to left-handed circular polarizations and summing the out-of-plane spin distributions. The findings offer opportunities for the visualization of magnetic domain structure with polar orientation of magnetization and in turn for the development of novel photonic spin topologies using complex magnetization patterns.
Open Access
A nonlocal metasurface for optical edge detection in the far-field

September 19, 2025

Doyoon Lee, Huu Lam Phan, Minkyung Kim

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Recent studies on nonlocal metasurfaces have shown possibilities of optical image processing, such as edge detection, without the need for Fourier optics and have significantly reduced the form factor. However, the analog edge detection using nonlocal metasurfaces still requires the use of multiple lenses to image the edge-enhanced results, and the edge-detected image generally suffers from image distortion originating from the free space propagation before reaching the detector otherwise. In this work, we propose a nonlocal metasurface that not only enhances the edge features but also delivers them to the far-field with considerably less distortion by combining the conventional edge detection metasurface with a uniaxial slab that has a transfer function of the free space with a negative propagation length. This space expander cancels out the diffraction of the edge-enhanced image that occurs during the free space propagation, the thickness of which reaches several orders of magnitude larger than the slab thickness. This nonlocal metasurface for the far-field edge detection will open a path towards compact optical systems for high-quality analog image processing.
Open Access
Geometric phases and coherent states for commensurate bichromatic polarization and astigmatic cavities

September 22, 2025

Miguel A. Alonso

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Both the polarization state of coherent bichromatic fields produced by harmonic generation and a class of anisotropic paraxial optical cavities are examples of commensurate two-dimensional harmonic oscillators. The geometric phase for these systems is studied here, both in the classical/ray and quantum/wave regimes. The quantum geometric phase is described in terms of the coherent states of the system, for which recursive expressions are derived that yield the exact result and are numerically stable even for high modal orders.
Open Access
Ultra-wideband TFLN modulator with selectively removed slab based on multifunctional BCB platform for high coupling efficiency and suppressed EO relaxation

December 4, 2025

Yutong He, Hao Liu, Changzheng Sun, Bing Xiong, Zhibiao Hao, Jian Wang, Lai Wang, Yanjun Han, Hongtao Li, Lin Gan, Jiyuan Zheng, Yi Luo

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Thin-film lithium niobate (TFLN) has a proven record of building high-performance electro-optic (EO) modulators. However, it has consistently posed challenges in securing low driving voltage, wide electro-optic bandwidth, low insertion loss, and high modulation efficiency simultaneously. Here, we demonstrate a telecom-wavelength EO modulator on the TFLN platform incorporating multifunctional benzocyclobutene (BCB) material. The low dielectric constant (low-k) BCB effectively reduces RF loss of the modulator and enables perfect velocity matching with a narrow electrode gap, thereby overcoming the conventional voltage–bandwidth trade-off. Meanwhile, in combination with a bilayer inversely tapered waveguide, it also facilitates the realization of high-efficiency edge couplers, significantly reducing the coupling loss of the modulator. In addition, the underlying TFLN slab is selectively removed to eliminate dielectric relaxation, ensuring a stable low-frequency EO response and bias-drift-free operation. The fabricated 13-mm-long modulator exhibits low half-wave voltages V π of 1.5 V in the C-band and 1.19 V in the O-band, corresponding to half-wave voltage-length products of 1.95 V·cm and 1.55 V·cm, respectively. Thanks to the BCB-clad edge coupler, an ultra-low coupling loss of 0.54 dB per facet is obtained. Ultra-wide EO bandwidths exceeding 110 GHz across the C + O-bands are demonstrated, and high-speed PAM8 data transmission with data rates up to 390 Gbit/s is successfully recorded in both C- and O-bands. The proposed modulator architecture not only delivers excellent overall performance, but also simplifies the fabrication process and expands the application potential.
Open Access
Nanogap-enhanced terahertz suppression of superconductivity

December 8, 2025

Joonyoung Kim, Gangseon Ji, Hyoung-Taek Lee, Jeonghoon Kim, Han-Seok Park, Uksam Choi, Choongwon Seo, Changhee Sohn, Kyungwan Kim, Byeongwon Kang, Hyeong-Ryeol Park

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Superconductivity collapses when all Cooper pairs acquire energies exceeding the superconducting gap. Breaking these pairs requires photons with energy greater than the superconducting gap or strong terahertz (THz) electric fields, which has limited the practical use of superconducting devices at THz frequencies. Here, we show that GdBa 2 Cu 3 O 7-δ (GdBCO) film integrated with 15-nm metal nanogaps exhibit Cooper pair breaking at 20 K, which is lower than its critical temperature T c , under incident THz fields as low as 60 V/cm. It should be noted that the extracted optical constants of the nanogap-integrated film exhibit a characteristic of a non-superconducting state, in contrast to the bare GdBCO film. This suppression of the superconductivity cannot be attributed to heating or fabrication damage but instead arises from the nanogap-enhanced THz fields delivering ponderomotive energy beyond the superconducting gap. Our results establish a non-thermal, low-field pathway for controlling superconductivity, opening opportunities for highly sensitive superconducting optoelectronic devices such as a THz single photon detector.
Open Access
Inverse-designed gyrotropic scatterers for non-reciprocal analog computing

November 28, 2025

Nikolas Hadjiantoni, Heedong Goh, Stephen M. Hanham, Miguel Navarro-Cía, Andrea Alù

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While conventional von Neumann based machines are increasingly challenged by modern day requirements, electromagnetic analog computing devices promise to provide a platform that is highly parallel, efficient and fast. Along this paradigm, it has been shown that arrays of subwavelength electromagnetic scatterers can be used as solvers of partial differential equations. Inverse design offers a powerful tool to synthesize such analog computing machines, utilizing engineered non-local responses to produce the solution of a desired mathematical operation encoded in the scattered fields. So far, this approach has been largely restricted to linear, reciprocal scatterers, limiting its generality and applicability. Here we demonstrate how arrays of gyrotropic scatterers can be used to solve a more general class of differential equations. Through inverse design, with a combination of evolutionary and gradient based algorithms, the position of the scatterers is optimized to achieve the desired kernel response. Introducing gyrotropic media, we also demonstrate improved accuracy by >2 orders of magnitude compared to similarly sized reciprocal systems designed with the same method.
Open Access
Light-amplification-assisted sum-frequency generation in erbium-doped thin-film lithium niobate optical waveguides

November 14, 2025

Yan Liu, Zhenzhong Hao, Xiao Wu, Shuting Kang, Rui Ma, Yuchen Zhang, Hongde Liu, Dahuai Zheng, Yongfa Kong, Fang Bo, Guoquan Zhang, Jingjun Xu

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Erbium-doped thin-film lithium niobate (Er 3+ :TFLN) enables integrated photonic devices through its efficient photoluminescence. However, the fixed transition energies of erbium ions intrinsically restrict emission to the telecommunications C-band (1530–1565 nm), limiting spectral versatility. To transcend this constraint, we engineered periodically poled Er 3+ :TFLN waveguides that concurrently integrate optical amplification and nonlinear frequency conversion. Within this platform, we harnessed erbium ions stimulated emission under 980 nm pumping to achieve net optical gain (0.8 dB) at 1538.2 nm. Simultaneously, we exploited the quasi-phase-matching (QPM) capability of the poled structure to perform sum-frequency generation (SFG) between the 976.0 nm pump and the amplified 1538.2 nm signal. This dual-process yielded visible emission at 597.1 nm with 84 nW output power and a normalized conversion efficiency of 68 % W −1  cm −2 . Critically, this work demonstrates-for the first time in Er 3+ :TFLN-spectral extension beyond the C-band through synergistic pump amplification and nonlinear mixing. Our monolithic architecture establishes a new paradigm for broadband on-chip photonics, enabling applications including multi-wavelength laser sources, quantum entangled photon pair generators, and on-chip biophotonic sensing systems.
Open Access
Orbital frontiers: harnessing higher modes in photonic simulators

November 4, 2025

Jiho Noh, Julian Schulz, Wladimir Benalcazar, Christina Jörg

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Photonic platforms have emerged as versatile and powerful classical simulators of quantum dynamics, providing clean, controllable optical analogs of extended structured (i.e., crystalline) electronic systems. While most realizations to date have used only the fundamental mode at each site, recent advances in structured light – particularly the use of higher-order spatial modes, including those with orbital angular momentum – are enabling richer dynamics and new functionalities. These additional degrees of freedom facilitate the emulation of phenomena ranging from topological band structures and synthetic gauge fields to orbitronics. In this perspective, we discuss how exploiting the internal structure of higher-order modes is reshaping the scope and capabilities of photonic platforms for simulating quantum phenomena.
Open Access
Near-unity fueling light into a single plasmonic nanocavity

November 6, 2025

Haiming Ye, Junhao Ge, Zhengyi Lu, Dudu Song, Jiamin Ji, Zhaoyang Peng, Shunping Zhang, Hongxing Xu

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Plasmonic nanocavities have emerged as a powerful platform for extreme light confinement, enabling transformative applications in single-molecule Raman spectroscopy, ultra-sensitive sensing, strong light–matter interactions, etc. By harnessing localized surface plasmons, these nanostructures support unprecedented field enhancement, exceeding 1,000-fold in the sub-nanometer gap. However, a fundamental trade-off exists between deep sub-wavelength field localization and its efficient coupling to free-space light, limiting their practical performance. Here, we show that by balancing the electric and magnetic resonance, more than 55 % of a focused Gaussian beam can be fueled into a nanocube-on-mirror nanocavity. With few concentric gratings, the coupling efficiency can even go up to >95 % at optimal conditions. This design can work at both visible and telecommunication wavelengths and show robust tolerance to fabrication imperfections. Our work indicates that the long-standing conflict between deep field localization and efficient external coupling in plasmonic systems can be resolved by multiscale structure design, promising the use of a single metal nanoparticle for advanced nanophotonic or optoelectronic devices.
Open Access
High pump depletion second-harmonic generation using domain engineered thin-film lithium niobate waveguides

November 19, 2025

Chenyu Wang, Mengwen Chen, Xiao-Hui Tian, Zishuo Gu, Jie Tang, Yong Zhang, Zikang Wang, Kunpeng Jia, Chenyang Shi, Xiaowen Gu, Guang Qian, Zhenlin Wang, Shi-Ning Zhu, Zhenda Xie

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Thin-film lithium niobate (TFLN) has emerged as a powerful platform for integrated nonlinear optics owing to its large χ (2) nonlinearity, tight confinement and flexible tunability. To fully excavate such superior nonlinear optical properties, domain engineering is commonly adopted to fulfill the phase matching condition of χ (2) processes. During the past decade, various domain engineered TFLN nonlinear optical devices have been demonstrated, showing extremely high length-normalized nonlinear optical conversion efficiencies. However, application-driven scenarios demand absolute energy conversion in nonlinear frequency conversion rather than length-normalized efficiencies, but the progress has been limited by imperfect fabrication processes. In this work, we realize effective on-chip nonlinear energy conversion by developing low-loss and high-quality domain engineered TFLN waveguides with long interaction length. Ion beam trimming (IBT) technique and an etching-prior-poling workflow are adopted for such fabrication. Optical characterization yields an overall second-harmonic generation (SHG) efficiency of 2,590 %/W. A high pump depletion of 85.7 % is demonstrated under continuous-wave operation, which directly reflects strong nonlinear energy conversion. These results may lead to breakthroughs in applications like classical optical frequency conversion, quantum frequency conversion, and quantum light generation.
Open Access
Engineering super- and sub-radiant hybrid plasmons in a tunable graphene frame-heptamer metasurface

October 27, 2025

Jiayi Gui, Na Chen, Hanchao Teng, Zhuoxin Xue, Shuang Xi, Chengyu Jiang, Shenghan Zhou, Hualong Zhu, Hai Hu

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Controlling near-field electromagnetic interactions is central to tailoring optical responses in plasmonic systems. However, the static nature of conventional noble metal nanostructures limits their application in active photonic devices. In this work, we design and experimentally demonstrate a composite graphene metasurface, composed of an octagonal frame coupled to a central heptamer disk, that enables multidimensional and active control over hybrid plasmons. The observed rich spectral features originate from hybridization between the dipolar and higher-order modes of the frame and the collective resonances of the heptamer. We show that the polarization of incident light serves as an effective control parameter for engineering the radiative properties of these modes. By varying the polarization angle, specific resonances can be selectively driven into super-radiant states with enhanced radiation or sub-radiant states with suppressed emission. In parallel, electrostatic gating provides a second, independent tuning mechanism that enables wide, continuous, and robust spectral modulation, in excellent agreement with theoretical predictions. The combined use of structural design, polarization control, and electrical tuning transforms a static metasurface into a dynamically reconfigurable platform. This dual control over both resonance frequency and radiative coupling offers a comprehensive toolkit for on-demand manipulation of light–matter interactions, paving the way for advanced optical modulators, reconfigurable filters, and tunable sensing technologies.
Open Access
Dual-polarization electromagnetic window simultaneously with extreme in-band angle-stability and out-of-band RCS reduction empowered by flip-coding metasurface

October 28, 2025

Heng-Yang Luo, Tie-Fu Li, Jia-Fu Wang, Yu-Xiang Jia, Rui-Chao Zhu, Xiao-Long Liang, Zhi-Hui Zhang, Min Zhou, Shao-Bo Qu

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Achieving high electromagnetic (EM) wave transmission with excellent angular stability is crucial for communication, detection, and guidance but remains challenging, especially when integrating other functions like out-of-band radar cross-section (RCS) reduction, which often degrades transmission. In this work, we propose to solve this problem by utilizing the longitudinal design freedom of metasurface. To this end, a typical longitudinally-coupled structure is proposed as the meta-atom for designing metasurfaces, which is composed of one layer of metallic meshes and one layer of metallic patch. By leveraging the synergistic effect of the plasma oscillation of the metallic mesh and the Lorentz resonance effect of the metal patch within meta-atom, we obtain a dual-polarization angle stable EM window (0°–80°) within the operating band. On this basis, without altering the structural parameters of the meta-atom, we utilize the longitudinal dimension to encode the reflection phases of out-of-band EM waves by flipping the meta-atom structure longitudinally, which can integrate out-of-band radar cross-section (RCS) reduction function without affecting the in-band transmission performance. To demonstrate this idea, prototypes were designed, fabricated and measured. Fabricated prototypes show good agreement between measurements and simulations, validating the method. This opens new paths for multifunctional EM windows in next-gen communication and radar systems.
Open Access
Record-level, exceptionally broadband borophene-based absorber with near-perfect absorption: design and comparison with a graphene-based counterpart

November 10, 2025

Amir Ali Marefati, Mahdieh Bozorgi

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We present a high performance ultra-broadband optical absorber based on a metal–insulator–metal (MIM) configuration, enhanced by two-dimensional (2D) materials: graphene and borophene. The base design includes a titanium resonator, an SiO 2 dielectric spacer, and a gold ground plane. Performance optimization is achieved through integration of 2D materials, anti-reflection coatings (ARC), and tuning of structural parameters, Fermi energy, and surface carrier density. Numerical simulations using the finite difference time domain (FDTD) method show that incorporating borophene, due to its exceptionally high carrier density, leads to remarkable enhancement in both absorption amplitude and spectral bandwidth. When integrated with an optimized antireflection coating (ARC), the borophene-based absorber achieves over 90 % absorption across 790–3,232 nm (bandwidth: 2,442 nm), corresponding to a 136 % enhancement over the base design. For absorption above 80 %, the bandwidth extends from 760 to 3,306 nm (2,546 nm), yielding a 125 % improvement. The associated fractional bandwidths are 121 % and 125 %, respectively. By comparison, the graphene-based counterpart, with a properly tuned ARC and Fermi level, delivers over 90 % absorption within 923–2,108 nm (1,185 nm, 13 % improvement), while maintaining absorption above 80 % across 911–2,256 nm (1,345 nm, 12 % improvement), with corresponding fractional bandwidths of 78 % and 84 %. Comparative analysis underscores the critical importance of 2D material selection and placement, ARC and resonator optimization, and optical tuning in achieving optimal performance. These results indicate strong potential for practical applications in advanced optoelectronic and photonic devices, including infrared imaging, optical sensing, broadband photodetectors, solar energy harvesting, and stealth or thermal camouflage systems.
Open Access
Atomic state interferometry for complex vector light

November 7, 2025

Kuntal Samanta, Sphinx J. Svensson, Sonja Franke-Arnold, Niclas Westerberg

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Features of complex vector light become important in any interference effects, including scattering, diffraction, and nonlinear processes. Here, we are investigating the role of polarization-structured light in atomic state interferometers. Unlike optical or atomic path interferometers, these facilitate local interference between atomic transition amplitudes and hence the orthogonal optical polarization components driving these transitions. We develop a fully analytical description for the interaction of generalized structured light with an atomic four state system, that is, multiply connected via optical as well as magnetic transitions. Our model allows us to identify spatially dependent dark states, associated with spatially structured absorption coefficients, which are defined by the geometry of the polarization state and the magnetic field direction. We illustrate this for a range of optical beams including polarization vortices, optical skyrmions, and polarization lattices. This results in a new interpretation and an enhanced understanding of atomic state interferometry, and a versatile mechanism to modify and control optical absorption as a function of polarization and magnetic field alignment.
Open Access
Disentangling the absorption lineshape of methylene blue for nanocavity strong coupling

November 25, 2025

Santiago A. Gomez, Emmi K. Pohjolainen, Dmitry Morozov, Ville Tiainen, J. Jussi Toppari, Gerrit Groenhof

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Cucurbit[7]uril molecules form non-covalent host – guest complexes with small molecular dyes. In addition, cucurbit[7]uril can also bind gold nanoparticles on gold surfaces with a 0.9 nm gap, creating plasmonic nanocavities for the dyes, with extreme confinement of the electromagnetic field. For methylene blue in such cavities, single molecule strong coupling was inferred from a complete disappearance of a characteristic shoulder in its spectrum, attributed to dimer removal. Yet, the shoulder’s origin remains debated. Using atomistic simulations, we show that it arises from both dimerization and vibronic progression. While cucurbit[7]uril binding removes the dimer contribution, vibronic progression persists. As this conflicts with previous reports, we also measured the spectra. In line with our computations, the shoulder remains visible when cucurbit[7]uril binds methylene blue. These results clarify the spectral features and pave the way for atomistic models of single-molecule strong coupling in nanoparticle-on-mirror cavities.
Open Access
Theory of dynamical superradiance in organic materials

December 8, 2025

Lukas Freter, Piper Fowler-Wright, Javier Cuerda, Brendon W. Lovett, Jonathan Keeling, Päivi Törmä

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We develop the theory of dynamical superradiance – the collective exchange of energy between an ensemble of initially excited emitters and a single-mode cavity – for organic materials where electronic states are coupled to vibrational modes. We consider two models to capture the vibrational effects: first, vibrations treated as a Markovian bath for two-level emitters, via a pure dephasing term in the Lindblad master equation for the system; second, vibrational modes directly included in the system via the Holstein–Tavis–Cummings Hamiltonian. By exploiting the permutation symmetry of the emitters and weak U(1) symmetry, we develop a numerical method capable of exactly solving the Tavis–Cummings model with local dissipation for up to 140 emitters. Using the exact method, we validate mean-field and second-order cumulant approximations and use them to describe macroscopic numbers of emitters. We analyze the dynamics of the average cavity photon number, electronic coherence, and Bloch vector length and show that the effect of vibrational mode coupling goes beyond simple dephasing. Our results show that superradiance is possible in the presence of vibrational mode coupling; for negative cavity detunings, the vibrational coupling may even enhance superradiance. We identify asymmetry of the photon number rise time as a function of the detuning of the cavity frequency as an experimentally accessible signature of such vibrationally assisted superradiance.
Open Access
Subharmonic injection-locked photonic integrated thin-film lithium niobate optoelectronic oscillator

November 19, 2025

Zijun Huang, Rui Ma, Qiang Ying, Peng Hao, Wei Ke, Xinlun Cai, X. Steve Yao

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Integrated optoelectronic oscillators (OEOs) have emerged as pivotal enablers of compact, energy-efficient solutions for generating high-frequency radio-frequency (RF) signals with exceptional spectral purity – an essential demand in the advancement of radar and communication technologies. Yet, the quest for ultra-low phase noise near the carrier remains hampered by laser frequency instability and environmental fluctuations. In this work, we unveil the first photonic-integrated, high-order subharmonic injection-locked OEO realized on a thin-film lithium niobate (TFLN) platform, seamlessly uniting a Mach–Zehnder modulator (MZM) and an add-drop microring resonator (MRR) in a monolithic architecture. By harnessing an external RF source operating at a fractional subharmonic (1/2 N , with N = 1, 3, 5…) of the OEO’s free-running frequency, our system achieves robust locking to the 2 N -th harmonic of the injected signal, made possible through the beating of ± N -th order modulation sidebands – precisely selected by the dual resonances of the MRR – at the photodetector. We experimentally demonstrate the generation of 28.7 GHz signals via second- and sixth-order subharmonic injection locking, employing external RF injections at 14.35 GHz and 4.78 GHz, respectively. This yields an outstanding side-mode suppression ratio (SMSR) exceeding 78 dB and remarkably low spurious emissions. Furthermore, the measured phase noise achieves values below −80 dBc/Hz at 100 Hz and below −115 dBc/Hz at 10 kHz offsets from the 28.7 GHz carrier, delineating a new standard for integrated OEO performance.
Open Access
Deep-learning-based polarization-dependent switching metasurface in dual-band for optical communication

November 18, 2025

Yihan Yan, Yunkai Wu, Yangwen Wang, Jiahao Li, Jingtian Hu, Xu Wang

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To address the critical limitations of conventional band-switching technologies – such as their slow speed, high energy consumption, and mechanical instability – this research introduces a novel deep-learning-driven framework for the intelligent inverse design of polarization-multiplexed metasurfaces. This approach represents a paradigm shift from traditional methods by enabling single-step, computational discovery of metasurface designs that directly encode two distinct optical functions within a single flat device. At the heart of our framework is a custom-designed deep neural network that seamlessly integrates parallel convolutional layers for robust feature extraction with cascaded regression modules for high-precision prediction. This hybrid architecture allows us to engineer sub-wavelength meta-atoms to achieve desired optical responses rigorously. As a groundbreaking demonstration, we designed and optimized a metasurface that achieves dynamic band switching solely through polarization modulation: it generates a targeted transmission peak in the O-band (1,260–1,360 nm) under y -polarization and an independent peak in the C-band (1,530–1,565 nm) under x -polarization. This mechanism eliminates the need for moving parts. The resulting device exhibits a switching efficiency orders of magnitude greater than its mechanical counterparts, while simultaneously offering enhanced stability, lower power consumption, and inherent adaptability for reconfigurable optical networks. Our work not only validates a specific device but also establishes a robust and generalizable design paradigm, underscoring the transformative potential of uniting deep learning with metasurfaces to achieve ultra-fast, intelligent, and efficient photonic systems for next-generation optical communications.
Open Access
Diffraction order-engineered polarization-dependent silicon nano-antennas metagrating for compact subtissue Mueller microscopy

December 3, 2025

Qingyuan Li, Jianyao Li, Gaodi Chen, Zhiguang Lin, Dongmei Lu, Xiaoxu Deng

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A polarization-dependent silicon nano-antennas metagrating (PSNM) is proposed for parallel polarization transformation by engineering diffraction orders, upon which a compact Mueller microscopy system is implemented for subtissue-level polarization extraction. The polarization-dependent metagrating is designed using matrix Fourier optics and nonlinear optimization with four diffraction orders described by waveplate-like Jones matrices, which is encoded by nano-antennas combining geometric and propagation phases. The measured phase delay and orientation of each diffraction order of the metagrating deviate by less than 6.7 % from the design values, and the overall diffraction efficiency reaches 70.89 % with a coefficient of variation of 0.021. A transmissive PSNM Mueller microscopy system is developed by directly embedding the metagrating into an infinity-corrected microscopic optical path, which extracts subtissue-level polarization distributions of biological sections over a 152 μm × 152 μm field of view with reduced measurement redundancy, facilitating the differentiation and staging of pathological tissues for potential stain-free diagnostic applications.
Open Access
Integrated array of coupled exciton–polariton condensates

November 19, 2025

Pietro Tassan, Etsuki Kobiyama, Jan David Fischbach, Dario Ballarini, Luca Moretti, Lorenzo Dominici, Milena De Giorgi, Daniele Sanvitto, Michael Forster, Ullrich Scherf, Antonis Olziersky, Carsten Rockstuhl, Thomas Jebb Sturges, Rainer F. Mahrt, Darius Urbonas, Thilo Stöferle

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A central challenge for advancing polariton-based circuits is the controlled and scalable coupling of individual condensates. Existing approaches based on etched or epitaxially grown microcavities are fabrication-intensive and restrict in-plane coupling. To overcome these limitations, we introduce a lithographically defined silicon-based platform of high-contrast grating (HCG) microcavities with a ladder-type π-conjugated polymer. In this system, doublet cavities exhibit mode hybridization into bonding and antibonding states, where coupling is mediated across shared HCG mirrors. Extending the design to arrays, N -coupled condensates exhibit systematic red-shifts of the condensate energy, due to delocalization, and a progressive threshold reduction, consistent with extended binding modes. Our experimental results are quantitatively supported by transition-matrix multi-scattering simulations, together with tight-binding modelling. First-order coherence measurements using Michelson interferometry confirm the existence of spatially extended condensates with exponentially decaying temporal coherence. Altogether, these results establish a scalable route toward integrated polariton devices and quantum photonic networks.
Open Access
Topological decomposition and transformation of photonic quasicrystals

October 30, 2025

Hao Wang, Houan Teng, Jinzhan Zhong, Xinrui Lei, Qiwen Zhan

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Photonic quasicrystals, generated through the interference of multiple vortex beams, exhibit rich and complex topological landscapes. However, unlike their periodic counterparts, they have far lacked the same level of controllability and reconfigurability. In this work, we develop a theoretical model to characterize the spin topology of photonic quasicrystals and uncover the intrinsic substructure underlying their quasi-periodic spin textures. By analyzing the formation mechanisms, we demonstrate the controlled decomposition and topological annihilation of individual sublattices within a quasicrystalline configuration. Based on this, we propose a phase-modulation method to reconfigure these topological states. We demonstrate that a quasicrystal with octagonal symmetry can be decomposed into two square meron lattices with a relative twist. This method is further extended to create more complex quasicrystals, where selective sublattice activation leads to meron bags. These findings provide new insights into both the static design and active manipulation of topological quasicrystals of light, paving the way for programmable topological photonic platforms with high spatial complexity and functional versatility.
Open Access
Squeezed light generation in periodically poled thin-film lithium niobate waveguides

October 31, 2025

Xiaodong Shi, Angela Anna Baiju, Xu Chen, Sakthi Sanjeev Mohanraj, Sihao Wang, Veerendra Dhyani, Biveen Shajilal, Mengyao Zhao, Ran Yang, Yue Li, Guangxing Wu, Hao Hao, Victor Leong, Ping Koy Lam, Di Zhu

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Squeezed states of light play a key role in quantum-enhanced sensing and continuous-variable quantum information processing. Realizing integrated squeezed light sources is crucial for developing compact and scalable photonic quantum systems. In this work, we demonstrate on-chip broadband vacuum squeezing at telecommunication wavelengths on the thin-film lithium niobate (TFLN) platform. Our device integrates periodically poled lithium niobate (PPLN) nanophotonic waveguides with low-loss edge couplers, comprising bilayer inverse tapers and an SU-8 polymer waveguide. This configuration achieves a fiber-to-chip coupling loss of 1.4 dB and a total homodyne detection loss of 4.0 dB, enabling a measured squeezing level of 1.4 dB. Additional measurements in a more efficient PPLN waveguide (without low-loss couplers) infer an on-chip squeezing level of approximately 10 dB at a pump power of 62 mW. These results underscore the potential of TFLN platform for efficient and scalable squeezed light generation.
Open Access
Polarization-dependent gain characterization in x-cut LNOI erbium-doped waveguide amplifiers

November 25, 2025

Jiayu Huang, Run Li, Suo Wang, Qianqian Jia, Zichuan Xiang, Jinling Yang, Jinye Li, Jianguo Liu

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Erbium-doped waveguide amplifiers (EDWAs) are vital for photonic integration, yet most are built on z-cut lithium niobate, incompatible with the mainstream x-cut platform. This work presents a combined theoretical and experimental study of polarization-dependent gain in x-cut Er:LNOI. Using Judd–Ofelt theory, we analyze how crystal orientation governs TE-mode coupling to Er 3+ ions, predicting stark differences in transition strengths between α - and π -polarizations. Experiments confirm these predictions: at 1,531 nm, the absorption and emission cross sections for α -polarization are 1.8 times larger than for π -polarization. At 1,550 nm, the α -polarization shows a gain coefficient of 3.3 dB/cm versus 2.2 dB/cm for π -polarization. In the small-signal regime, the α -polarized amplifier achieves 32.01 dB signal enhancement with 11.18 dB internal net gain. With 9.1 dBm on-chip input power, it delivers 21.18 mW unsaturated output power under pumping levels exceeding 200 mW. This work demonstrates feasible optical amplification on x-cut LNOI, providing crucial support for large-scale photonic and microwave photonic systems.
Open Access
Spin angular momentum modulation via spin–orbit interaction in fractional orbital angular momentum beams

November 10, 2025

Xusheng Chen, Fanfei Meng, Kang Du, Min Lin, Luping Du

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Light exhibits both spin and orbital angular momentum (SAM and OAM). These two forms of angular momentum remain independent in paraxial fields, but become coupled in confined fields through spin–orbit interactions (SOI). The SOI mechanism allows for the manipulation of SAM to generate structured light fields featuring nontrivial topological characteristics, such as optical skyrmions. Conventional OAM beams, nonetheless, carry discrete integer topological charges (TCs), leading to discrete SAM states. This discrete property poses a persistent challenge for achieving continuous control of SAM. To tackle this fundamental issue, we explored fractional orbital angular momentum (FOAM) beams, whose TCs are extended from integers to fractions, to realize continuous and precise control of SAM. A direct mathematical relationship between the fractional effective TCs of FOAM beams and the orientation distributions of the SAM vector has been derived. This theoretical prediction has been experimentally verified using our home-built near-field mapping system, by which the distinct SAM distributions of surface cosine waves regulated by FOAM beams were mapped out. As a potential application, we also devised an inverse detection method to accurately measure the fractional effective TCs of FOAM, which achieved theoretical and experimental accuracies of 10 −5 and 10 −2 , respectively. These advancements may enhance our fundamental understanding of the SOI mechanism, and hence could create novel opportunities for light field manipulation, optical communication, and other related areas.
Open Access
Classification of quantum-spin-hall topological phase in 2D photonic continuous media using electromagnetic parameters

October 23, 2025

Xin-Tao He, Shuo-Shi Zhang, Xiao-Dong Chen, Jian-Wen Dong

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Refractive index is a fundamental electromagnetic (EM) parameter that can describe photonic continuous media (PCM) traditionally as either transparency or opacity. Recently, topological theory offers a new set of phases to characterize PCM as either trivial or nontrivial, by using topological invariant which are not direct to EM parameters. As all of the optical properties in PCM should be related to EM parameters, we formulate a topological index based on EM parameters and establish its phase map in this work. The map can analytically describe the deterministic condition for a topologically nontrivial phase. Our findings indicate that the topology of 2D bi-anisotropic PCM is determined by the sign of the topological index. Another EM parameter of pseudo surface impedance is also introduced for the opaque regions of PCM, showing the topological opacity has a full range of impedance values ranging from negative to positive, while the trivial case only has either negative or positive impedance. The simulation results show that an interface between two opacities with differing index signs can support robustly optical propagation of topological edge states. The proposal of EM-parameter method reveals a deep understanding on topological properties of PCM, and will enrich the topological theory in photonic systems.
Open Access
Gigahertz thermoelastic acousto-optic modulation in lithium niobate integrated photonic device

September 30, 2025

Zheng Zheng, Hanke Feng, Ahmet Tarık Işık, Peter J.M. van der Slot, Cheng Wang, David Marpaung

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Tailoring the interaction between acoustic waves and optical waves in integrated photonic circuits has emerged as a promising avenue for quantum optics and high-speed information processing. Among various approaches, on-chip acousto-optic modulation (AOM) has been extensively explored in the past decade and successfully demonstrated across many integrated photonics platforms. In this paper, we design and fabricate metallic gratings with periods varying from 0.4 μm to 3 μm deposited on a half-etched thin film lithium niobate (TFLN) device cladded by 1-μm thick silica. By illuminating the metallic grating with an intensity-modulated pump beam, we can generate thermoelastically driven SAWs with frequencies up to 6.58 GHz, and a linewidth of 1.8 MHz at a center frequency of 1.41 GHz. This thermoelastic approach eliminates reliance on a piezoelectric material response, offering broader compatibility for integrated photonics applications.
Open Access
Visualization of plasmonic diffraction-guided carrier dynamics in silicon photodetectors

November 26, 2025

Soh Uenoyama, Yusuke Yoshizawa, Kazunori Tanaka, Hiroyasu Fujiwara, Atsushi Ono

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Silicon-based photodetectors operating in the near-infrared (NIR) wavelength range ( λ = 700–1,100 nm) are essential for applications such as light detection and ranging, facial recognition, and eye-tracking. However, silicon’s low absorption coefficient in this range limits photodetection efficiency. While recent advances in nano-diffraction structures have improved photo-absorption by increasing the effective absorption path, optimizing carrier dynamics remains challenging. In the NIR regime, photons penetrate deeply into the silicon substrate, making it critical to align the spatial distribution of photo-generated carriers with the charge collection regions. However, the angular and spatial behavior of carrier generation (CG) and collection under nano-diffraction structures remain underexplored. This study presents an analytical model that visualizes CG pathways and corresponding collection probabilities induced by plasmonic diffraction structures, providing insight into diffraction-driven CG in silicon. The model is experimentally validated through photocurrent responses in non-illuminated neighboring pixels, directly revealing plasmonic diffraction effects. The results show that diffraction enhances light absorption and enables visualization of the CG and collection pathways based on the diffraction angle. This approach enables the spatial overlap of CG and collection pathways, efficiently guiding incident photons to photosensitive regions. This framework offers a new strategy to enhance NIR photodetector performance through diffraction-guided light propagation and device-specific modeling.
Open Access
Super-resolution imaging of resonance modes in semiconductor nanowires by detecting photothermal nonlinear scattering

November 27, 2025

Yu-An Chen, Te-Hsin Yen, Chun-Yu Yang, Jhih-Jia Chen, Chih‐Wei Chang, Kentaro Nishida, Shi-Wei Chu

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We demonstrated a far-field super-resolution optical imaging for mapping the resonance mode within semiconductor nanowires, where periodic distributions are found with good agreement between simulation and experiment. The pronounced absorption at the antinodes leads to localized photothermal heating, as well as consequent scattering nonlinearity via the thermo-optic effect. To break the diffraction limit, we combine the scattering nonlinearity with tightly focused laser scanning. Based on the principle of saturated excitation (SAX) microscopy, the nonlinear scattering signals are extracted to significantly improve the spatial resolution (1.7 fold), enabling visualization of the resonant modes that are not visible with conventional far-field optical imaging. Our results pave the way for optical inspection of semiconductor photonic integrated circuits with subdiffraction-limit spatial resolution.
Open Access
High-sensitivity U-shaped biosensor for rabbit IgG detection based on PDA/AuNPs/PDA sandwich structure

December 1, 2025

Pengxiang Chang, Yirui Zhang, Ailing Zhang, Zhen Li, Zhiyang Wang, Yanmei Shi

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Combining the advantages of polydopamine (PDA), gold nanoparticles (AuNPs), and U-shaped optical fibers, a PDA/AuNPs/PDA sandwich structure modified U-shaped optical fiber surface plasmon resonance (SPR) biosensor was proposed and used for the detection of rabbit IgG. The U-shaped structure significantly enhances the penetration depth of the evanescent field. The PDA/AuNPs/PDA sandwich structure boosts coupling efficiency of SPR and LSPR, increases the specific surface area of the sensor, and improves surface activity. The experimental results show that the refractive index (RI) sensitivity of the sensor is 6,206.32 nm/RIU in the RI range of 1.3353–1.3595, which is 1.63 times higher than the raw U-shaped sensor. The biosensor for detection of rabbit IgG achieved a biosensitivity of 0.153 nm/(ng/mL), which is two orders of magnitude higher and a limit of detection (LOD) of 0.131 ng/mL, which is one order of magnitude lower. The outstanding performance of the proposed biosensor offers a new solution for the detection of low-concentration biological solutions, and it has great potential applications in the field of medical diagnosis.
Open Access
Metastructure-enabled scalable multiple mode-order converters: conceptual design and demonstration in direct-access add/drop multiplexing systems

December 1, 2025

Zhenzhao Guo, Weike Zhao, Shengbao Wu, Yunfeng Lai, Shuying Cheng, Daoxin Dai

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The rapid advancement of multimode photonic technologies, optical computing, and quantum circuits, leveraging higher-order modes, necessitates the development of on-chip multiple mode-order converters (MMOCs). However, existing schemes face limitations in traffic capacity, polarization-dependence, and scalability. Herein, we propose a novel highly scalable MMOC design framework enabled by subwavelength grating (SWG) metastructures. By integrating SWG arrays into a taper-tailored multimode waveguide, the design synergizes coherent scattering and beam shaping to achieve efficient target-supermode excitations and precise phase controls, simultaneously. In this way, the target MMOC can be realized according to the functional requirements of mode manipulations by optimizing the metastructures. Experimentally fabricated devices exhibit ILs < 1.85 dB and CTs < −12.5 dB across (22 or 50) nm bandwidths, with a polarization-independent quad-mode operation. Notably, the dual-pair mode exchanging MMOC pioneers simultaneous TE 0 ↔TE 2 and TE 1 ↔TE 3 , doubling exchange efficiency over conventional single-pair solutions. Integrated into a direct-access mode add/drop system (DAMAD), TE 0 /TE 1 dual-mode add/drop operations achieve ILs < 4.5 dB and CTs < −15.5 dB across 41 nm bandwidth. Thereupon, clear eye diagrams at 32/64 Gbps operations demonstrate the capability for the high-speed optical communication. The proposed concept offers a novel strategy for on-chip multiple mode manipulations, with transformative potential in higher-order modes based optical communications.
Open Access
Modulation of the type and excitation region of plasmonic topological quasiparticles in a metasurface by tailoring the excitation light

July 4, 2025

Xinru An, Peng Lang, Xuefeng Shi, Boyu Ji, Feng Lin, Yihe Lin, Yang Xu, Xiaowei Song, Jingquan Lin

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We propose and demonstrate to manipulate the generation of plasmonic skyrmion and meron as well as their field spatial distribution with a metasurface composed of T-shaped nanoslit arrays by tuning the wavelength and spin of the excitation light. Simulation results show that plasmonic skyrmion and meron can be constructed and their field distribution can be manipulated within the proposed metasurface. Controllable unidirectional propagation of surface plasmon polaritons, which depends on the wavelength and spin of the incident circularly polarized light via the geometric phase introduced by the T-shaped nanoslit array, supports the formation of plasmonic topological quasiparticles. Scanning near-field optical microscope (SNOM) is employed to image the field profile of the plasmonic topological quasiparticles under the different excitation conditions, and it is found out that the field profile obtained by SNOM is in good agreement with the simulation result.
Open Access
Intramodal stimulated Brillouin scattering in suspended AlN waveguides

November 27, 2025

Han Xue, Chukun Huang, Haotian Shi, Jiaheng Fu, Tianheng Zhang, Junqiang Sun

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Aluminum nitride (AlN), a wide-bandgap III–V material, offers excellent transparency in the optical communication band and a favorable refractive index for strong optical confinement, making it a promising platform in stimulated Brillouin scattering (SBS). Here, we observe, for the first time, optically excited SBS in suspended AlN-on-silicon waveguides. A Brillouin gain coefficient of 91.8 m −1  W −1 is achieved at an acoustic frequency of 2.32 GHz, with a linewidth of 10.1 MHz. The Brillouin nonlinear response can be tailored by varying the waveguide dimensions. Furthermore, the Bragg grating–based Fabry–Pérot (FP) resonator enhances the gain coefficient to 150.37 m −1  W −1 and results in a narrowed linewidth of 9.87 MHz. These results not only validate the feasibility of strong intrinsic Brillouin interaction in suspended AlN waveguides but also pave the new way for CMOS-compatible on-chip Brillouin amplifiers, lasers, and isolators.
Open Access
Topological phase structures of conical refraction beams: expanding orbital angular momentum applications for nanoscale biosensing

November 25, 2025

Diana Galiakhmetova, Nawal Mohamed, Fatima Khanom, Shakti Singh, Gennadii Piavchenko, Grigorii S. Sokolovskii, Edik Rafailov, Igor Meglinski

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Topologically structured light carrying orbital angular momentum (OAM) has emerged as a powerful tool for nano-photonics and biomedical optics, yet conventional integer-charge Laguerre–Gaussian (LG) beams suffer from rotational degeneracy that limits diagnostic precision. Here, we demonstrate that conical refraction (CR) beams, specifically the Lloyd, Poggendorff, and Raman families, overcome this fundamental limitation through their inherent generation of fractional OAM states with unambiguous phase signatures. Through systematic interferometric comparison of LG ( ℓ = 3, 5) and CR beam propagation in tissues, we show that CR beams achieve superior diagnostic performance: while LG beams exhibit three-fold rotational ambiguity (4.19 rad uncertainty), Poggendorff CR beams provide phase determination with 0.08 rad precision. Both LG and CR beam families display remarkable topological resilience, preserving phase coherence as they traverse tissue samples while attaining refractive index sensitivity at the 10 −6 level, three orders of magnitude beyond conventional refractometry. Most significantly, we present the first experimental evidence that CR beams can discriminate between healthy and cancerous kidney tissues through distinct phase rotations (4.71 vs. 5.04 rad, p < 0.001) and a tenfold amplification in polarisation-induced distortion. The fractional topological charges of CR beams, ranging continuously between integer values, expand the accessible OAM phase space and enable 3.7-fold superior signal-to-noise ratio compared to LG 0 3 ${\text{LG}}_{0}^{3}$ measurements. These results establish CR-generated fractional OAM as the preferred modality for label-free tissue diagnostics, bridging fundamental nanophotonics with clinical applications in cancer detection and intraoperative margin assessment.
Open Access
Metasurface-based Fourier ptychographic microscopy

November 25, 2025

Cheng Hung Chu, Hao-Pin Chiu, Cheng Yu, Yuan-Chung Cheng, Ching-En Lin, Sunil Vyas, Yuan Luo

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Meta-optics have opened new possibilities for portable, high-performance microscopy, offering ultrathin and highly customizable wavefront control in scenarios where bulky optics limit adoption. Here, we use this capability to overcome the long-standing challenges of Fourier ptychography (FP), a powerful computational technique for wide-field, high-resolution quantitative phase imaging that traditionally depends on large optical elements and extensive angle scanning. Our compact meta-FP platform combines a 4-f metalens system for imaging miniaturization with a programmable thin-film transistor (TFT) panel to provide stable, angle-diverse plane-wave illumination without mechanical movement. To further accelerate imaging, we introduce a residual convolutional neural network (RCNN) model trained via transfer learning on conventional FP datasets, which allows for single-shot inference of high-resolution phase from low-resolution inputs. Experimental validations demonstrate nearly twofold resolution improvement (7.81 µm–3.91 µm), accurate quantitative phase recovery on phase standards with errors below 10 %, and dry-mass estimation of H1975 cells with an average deviation of approximately 12 %, while the best-performing regions exhibit deviations below 0.5 %. This integration of metasurface optics and artificial intelligence-driven reconstruction provides a promising pathway for fast and compact FP microscopy with applications in live-cell imaging, microfluidic monitoring, and point-of-care diagnostics.
Open Access
Broadband on-chip spectral sensing via directly integrated narrowband plasmonic filters for computational multispectral imaging

November 10, 2025

Qilin Zheng, Li Liang, Shunji Yang, Luyang Tong, Wenqiang Wang, Jibo Tang, Yu Zhang, Bintong Huang, Xiaobo He

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Spectroscopy underpins a wide range of applications, including biomedical diagnostics, precision agriculture, remote sensing, and industrial process control. Recent advances in silicon and microwave photonic integration have facilitated the miniaturization of spectroscopic systems, enabling portable, real-time analysis. However, the realization of a chip-scale platform that simultaneously achieves broadband coverage, high resolution, and scalable low-cost fabrication – particularly in the near-infrared (NIR) regime – remains a significant challenge. Here, we present a compact and cost-effective NIR spectroscopic sensing chip that monolithically integrates a plasmonic bandpass filter array with InGaAs photodetectors. The device is fabricated via single-step lithography and features a nanohole array with geometrically tunable narrowband transmission spanning 900–1,700 nm, exhibiting a full width at half maximum (FWHM) of 5.0 nm and a peak Q -factor of ∼284. The plasmonic filters are directly integrated with the detectors through a SiN x spacer layer, eliminating post-fabrication alignment and enhancing scalability. A 16-channel super-pixel layout, combined with computational spectral reconstruction, enables ∼1 nm resolution near 1,550 nm and supports high-fidelity spectral imaging. This work demonstrates a scalable, detector-compatible approach to on-chip NIR spectroscopy, offering a promising route toward deployable, compact spectral sensing platforms.
Open Access
Surface relief formation with light possessing multiple vortices

November 18, 2025

Junjie Zhao, Kazuro Kizaki, Atsushi Taguchi, Madoka Ono, Soki Hirayama, Takashige Omatsu

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We report the first demonstration of surface relief formation by irradiating material with non-degenerate hybrid vortex modes. These modes are formed via the coherent superposition of two Laguerre–Gaussian (LG) modes with different orbital angular momentum (OAM) indices, and they carry non-zero OAM. Intriguingly, the spatially localized vortex fields, which are associated with multiple phase singularities of the non-degenerate hybrid vortex modes and spin angular momentum (SAM) of circular polarization, can be visualized as fist-like protrusions produced within the fabricated surface relief structures. This demonstration offers new insights into fundamental light–matter interactions via SAM-OAM coupling effects and opens the door to a deeper understanding of the mechanisms underlying the formation of vortex lattices and vortex–antivortex pairs in condensed matter physics. This demonstration also provides a method for fabricating chiral surface relief structures with an odd number of spiral arms, which may be utilized in advanced optical data storage and chiral metasurface applications.
Open Access
A comprehensive study of plasmonic mode hybridization in gold nanoparticle-over-mirror (NPoM) arrays

December 4, 2025

Raphael Gherman, Sacha Schwarz, Jean-François Bryche, Guillaume Beaudin, Alex Currie, Pierre Levesque, François Fillion-Gourdeau, Steve G. MacLean, Dominique Drouin, Serge Ecoffey, Paul G. Charette

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Hybrid plasmonic systems that combine localized and propagative surface plasmons offer new opportunities for tunable light–matter interactions at the nanoscale. This paper provides the most comprehensive study to date of hybridization between gap localized surface plasmons (gap LSP) and diffraction-mediated propagative surface plasmon polaritons (SPP) in arrays of gold nanodisks over a mirror, part of the larger class of nanoparticle-over-mirror (NPoM) devices. By systematically mapping the hybrid mode dispersion as a function of array geometry over a large parameter space, we extract the coupling strength via a coupled oscillator model and reveal its dependence on key structural parameters, with gap thickness identified as the primary tuning factor. The resulting hybrid modes enhance the optical quality factor by nearly fivefold compared to classical LSP while maintaining strong near-field confinement, combining the advantages of their constituent modes. Dephasing times were measured with interferometric time-resolved photoemission electron microscopy (ITR-PEEM). Using a scalable lithography-compatible NPoM architecture that minimizes the optical index mismatch between the dielectric between the nanodisks and the gap material (Al 2 O 3 ), we achieved the highest coupling strength (123 meV) and dephasing time range (23–50 fs) to date in NPoM arrays.
Open Access
Light-guided spectral sculpting in chiral azobenzene-doped cholesteric liquid crystals for reconfigurable narrowband unpolarized light sources

December 4, 2025

Pravinraj Selvaraj, Ming-Hong Yuan, Cheng-Kai Liu, Ko-Ting Cheng

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Precise manipulation of Bragg reflection in cholesteric liquid crystals (CLCs) is essential for advancing reconfigurable optics. However, existing photo-responsive material-doped CLC technologies that rely on single-wavelength photoisomerization encounter several challenges, including slow response times, limited tunability, inadequate spatial control, and instability caused by pitch variations due to diffusion. Here, we present a robust dual-wavelength photoisomerization method to simultaneously achieve trans -to- cis and cis -to- trans photoisomerization of chiral azobenzene-doped CLCs, which enables broadband, reversible, and spatially addressable control over the Bragg reflection spectrum. By employing counterpropagating laser beams at 405 nm and 532 nm, we precisely control the trans – cis isomerization dynamics of azobenzene chiral dopants, achieving spectral shifts exceeding 100 nm primarily through reversible modulation of the helical pitch of the CLCs. Furthermore, manipulating the intensity ratio and geometry of the excitation beams allows for tailored pitch gradients, reflection bandwidths, and central wavelengths with remarkable fidelity. Our approach enhances pitch boundaries and reduces molecular diffusion, facilitating the micrometer-scale patterning of optical textures, which surpasses traditional single-wavelength methods. Additionally, we present an innovative narrowband spectral filtering technique by sequentially transmitting light through pitch-selective CLC regions under circular polarization control. This reconfigurable manipulation strategy paves the way for developing programmable photonic systems, including adaptive optics, diffractive optics, and tunable displays.
Open Access
Monolithic temperature-insensitive high-Q Ta₂O₅ microdisk resonator

December 5, 2025

Zhen Yang, Zheng Zhang, Peng Cheng, Zhe Long, Qi Cheng, Jiaqi Yang, Yu Lin, Bin Fang, Zhongming Zeng, Zhiping Zhou, Ganapathy Senthil Murugan, Rongping Wang

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We demonstrate a temperature-insensitive high- Q tantalum oxide (Ta 2 O 5 ) microdisk resonator fabricated using electron-beam lithography and inductively coupled plasma reactive-ion etching. The microdisks exhibit a loaded Q -factor of 4.25 × 10 5 at 1,550 nm, which more than doubles (∼9.3 × 10 5 ) following thermal annealing at 600 °C. Remarkably, the temperature-dependent resonant wavelength shift is suppressed to less than 10 pm/°C across a broad 100 nm bandwidth. Furthermore, the resonators maintain high optical stability under elevated input powers, with no observed degradation in optical properties such as extinction ratio or Q -factor. The combination of high Q -factors and exceptional thermal stability positions the Ta 2 O 5 microdisk resonators as a promising platform for integrated photonic device applications, including on-chip narrow-linewidth lasers and precision sensing.
Open Access
Large-gap cascaded Moiré metasurfaces enabling switchable bright-field and phase-contrast imaging compatible with coherent and incoherent light

December 2, 2025

Yiyi Li, Wangzhe Zhou, Yuqing Zhang, Xiaoyan Huang, Yutai Chen, Man Yuan, Junbo Yang

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Bright-field and phase-contrast imaging represent two of the most essential modes for target recognition and feature extraction, offering broad applicability in fields such as biomedicine and autonomous driving. In this work, we propose a cascaded Moiré metasurfaces system with a large interlayer spacing, which enables switchable bright-field and phase-contrast imaging at a wavelength of 532 nm by adjusting the illumination conditions between coherent and incoherent light sources. By employing an optimized phase-iterative algorithm, the stringent spacing requirement of conventional cascaded Moiré metasurfaces is relaxed from the subwavelength scale (∼100 nm) to beyond 1 mm, while maintaining robust imaging performance under spacing deviations of ±0.1 mm. Through controlled relative rotation of the two metasurfaces by an angle θ , the system dynamically switches between a focused solid Airy disk ( θ = 0°) and vortex beams with tunable topological charges ranging from −5 to +5 ( θ = ±20° to ±100°). The design achieves a focusing efficiency of 82 % and vortex beam purities up to 99 %. Owing to its versatile switching capability, the system supports multi-order edge extraction for both phase-type and amplitude-type objects, reaching a spatial frequency of 228 lp/mm. This approach overcomes the limitation of existing edge-detection metasurfaces, which operate only under either coherent or incoherent illumination. Our findings provide a new technical pathway toward compact, multifunctional, and integrated imaging devices.
Open Access
Nonlocal electrodynamics of two-dimensional anisotropic magnetoplasmons

October 15, 2025

André J. Chaves, Line Jelver, Diego R. da Costa, Joel D. Cox, N. Asger Mortensen, Nuno M.R. Peres

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We present a hydrodynamic model, grounded in Madelung’s formalism, to describe collective electronic motion in anisotropic materials. This model incorporates nonlocal contributions from the Thomas–Fermi quantum pressure and quantum effects arising from the Bohm potential. We derive analytical expressions for the magnetoplasmon dispersion and nonlocal optical conductivity. To demonstrate the applicability of the model, we examine electrons in the conduction band of monolayer phosphorene, an exemplary anisotropic two-dimensional electron gas. The dispersion of plasmons derived from our hydrodynamic approach is closely aligned with that predicted by ab initio calculations. Then, we use our model to analyze few-layer black phosphorus, whose measured infrared optical response is hyperbolic. Our results reveal that the incorporation of nonlocal and quantum effects in the optical conductivity prevents black phosphorus from supporting hyperbolic surface plasmon polaritons. We further demonstrate that the predicted wavefront generated by an electric dipole exhibits a significant difference between the local and nonlocal descriptions for the optical conductivity. This study underscores the necessity of moving beyond local approximations when investigating anisotropic systems capable of hosting strongly confined plasmon-polaritons.
Open Access
Permittivity-asymmetric qBIC metasurfaces for refractive index sensing

November 24, 2025

Xingye Yang, Alexander Antonov, Haiyang Hu, Andreas Tittl

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Bound states in the continuum (BICs) provide exceptional light confinement due to their inherent decoupling from radiative channels. Small symmetry breaking transforms BIC into quasi-BIC (qBIC) that couples to free-space radiation enabling ultra-high-quality-factor (Q-factor) resonances desirable for refractive index (RI) sensing. In practical implementations, geometric asymmetry is typically employed. However, since the radiative loss remains fixed once fabricated, such metasurfaces exhibit only a horizontal shift of the resonance spectrum in RI sensing, without modification of its overall shape. Here, we demonstrate a permittivity-asymmetric qBIC (ε-qBIC) metasurface, which encodes environmental refractive index variations directly into the asymmetry factor, resulting in an index response involving both resonance wavelength shift and modulation variation. In addition to exhibiting a competitive transmittance sensitivity of ∼5,300 %/RIU under single-wavelength conditions, the ε -qBIC design provides a substantially improved linear response. Specifically, the linear window area of its sensing data distribution, calculated as the integrated wavelength region where the linearity parameter remains above the preset threshold, is 104 times larger than that of the geometry-asymmetric qBIC (g-qBIC), enabling more robust and reliable single-wavelength signal readout. Additionally, numerical results reveal that environmental permittivity asymmetry can optically restore the g-qBIC to a state with ultra-high-Q (over 10 7 ), approaching the BIC condition. Unlike traditional BICs, which are typically inaccessible once perturbed, the permittivity-restored BIC becomes accessible through environmental perturbations. These findings suggest an alternative design strategy for developing high-performance photonic devices for practical sensing applications.
Open Access
Coexistence of weak and strong coupling in a photonic molecule through dissipative coupling to a quantum dot

November 27, 2025

Stefan Lichtmannecker, Santiago Echeverri-Arteaga, Michael Kaniber, Isabel C. Andrade Martelo, Joaquín Ruiz-Rivas, Thorsten Reichert, Günther Reithmaier, Per-Lennart Ardelt, Max Bichler, Eduardo Zubizarreta Casalengua, Edgar A. Gómez, Herbert Vinck-Posada, Elena del Valle, Kai Müller, Fabrice P. Laussy, Jonathan J. Finley

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We study the emission from a molecular photonic cavity formed by two proximal photonic crystal defect cavities containing a small number ( < 3 ) $(< 3)$ of In(Ga)As quantum dots. Under strong excitation, we observe photoluminescence from the bonding and antibonding modes in agreement with ab initio numerical simulations. Power dependent measurements, however, reveal an unexpected peak, emerging at an energy between the bonding and antibonding modes of the molecule. Temperature-dependent measurements indicate that this unexpected feature is photonic in origin. Time-resolved measurements show the emergent peak exhibits a lifetime τ M = 0.75(10) ns, similar to both bonding and antibonding coupled modes. Comparisons of experimental results with quantum optical modeling suggest that this new feature arises from a coexistence of weak and strong coupling, due to the molecule emitting in an environment whose configuration permits or, on the contrary, impedes its strong coupling. This scenario is reproduced theoretically with a master equation reduced to the key ingredients of its dynamics and that roots the mechanism to a dissipative coupling between bare modes of the system. Excellent qualitative agreement is obtained between experiment and theory, showing how solid-state cavity QED can reveal intriguing new regimes of light–matter interaction.
Open Access
High-capacity multiview display with large viewing angle via orbital angular momentum-encoded nanograting arrays

November 3, 2025

Yiqi Ye, Hang Su, Yuetian Jia, Baoli Li, Min Gu, Xinyuan Fang

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Three-dimensional (3D) displays reconstruct spatial light fields, providing immersive stereoscopic experiences with depth perception. Multiview 3D displays are particularly attractive, delivering multiple perspective images to different spatial positions for glasses-free multi-user observation and continuous motion parallax. However, achieving both high-capacity information encoding and a large field-of-view (FOV) remains challenging. Here, we propose a high-capacity, large-FOV holographic multiview 3D display by integrating orbital angular momentum (OAM) multiplexing with forked nanograting arrays fabricated via two-photon lithography (TPL). A 3 × 3 hologram array is loaded onto a spatial light modulator (SLM), with each sub-hologram encodes four orthogonal OAM modes, enabling parallel high-capacity information storage. Each OAM channel is diffracted by the corresponding forked nanograting array into multiple discrete directions (experimentally verified up to nine), effectively expanding the accessible viewing range. A dual dynamic control mechanism allows real-time hologram refresh on the SLM and selective switching of different OAM-encoded image sets without computational latency. Experiments under 532 nm illumination successfully reconstruct eight independent 3D scenes with nine viewpoints across a 30° field of view, achieving an average structural similarity index (SSIM) of ∼0.81 with negligible crosstalk. This work establishes a reconfigurable, high-throughput, large-FOV multiview 3D display framework, with potential for portable AR/VR devices, holographic communication and medical surgical navigation.
Open Access
Cross-polarized and stable second harmonic generation from monocrystalline copper

November 19, 2025

Elif Nur Dayi, Omer Can Karaman, Diotime Pellet, Alan R. Bowman, Giulia Tagliabue

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Second-harmonic generation (SHG) is a powerful surface-specific probe for centrosymmetric materials, with broad relevance to energy and biological interfaces. Plasmonic nanomaterials have been extensively utilized to amplify this nonlinear response. Yet, material instability has constrained most studies to gold, despite the significance of plasmonic metals such as copper for catalysis. Here, we demonstrate stable and anisotropic SHG from monocrystalline copper, overcoming long-standing challenges associated with surface degradation. By leveraging an on-substrate synthesis approach that yields atomically flat and oxidation-resistant Cu microflakes, we enable reliable SHG measurements and reveal a strong cross-polarized response with C 3 v surface symmetry. The SHG signal remains stable over 3 h of continuous femtosecond excitation, highlighting the remarkable optical robustness of the Cu microflakes. These results reinforce the viability of monocrystalline Cu as a robust platform for nonlinear nanophotonics and surface-sensitive spectroscopy, expanding the range of copper-based optical applications.
Open Access
Polarization-encoded color images for information encryption enabled by HfN refractory plasmonic metasurfaces

November 10, 2025

Yu-Cheng Chu, Tzu-Yu Peng, Chen-Yu Wang, Shyr-Shyan Yeh, Jia-Wern Chen, Yu-Jung Lu

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Polarization control plasmonic nanostructures provide a unique route to manipulate light–matter interactions at the nanoscale and are particularly powerful for information security applications, where polarization-encoded color images can be used for optical encryption and anticounterfeiting. Conventional plasmonic materials such as Au and Ag, however, suffer from poor thermal stability, limiting their integration into robust, CMOS-compatible devices. Here, we present a polarization-encoded color image platform based on refractory HfN plasmonic metasurfaces, which combine gold-like optical properties with exceptional hardness, compositional tunability, and superior high-temperature resilience. Periodically patterned HfN nanoantennas with widths of 200 nm exhibit well-defined localized surface plasmon resonances in the visible spectrum (628 and 564 nm) and can be selectively excited by orthogonal linear polarizations. We designed and realized a polarization-encoded color image in which distinct color channels are revealed under x- and y-polarized illumination, enabling decryption of hidden information. Under unpolarized illumination, the superposition of color channels effectively conceals the message, achieving robust optical encryption. Our results establish HfN plasmonic nanostructures as a key material platform for next-generation nanophotonics, uniquely combining gold-like optical properties with exceptional thermal robustness. Even after high-temperature annealing, HfN retains its plasmonic response, enabling reliable polarization-resolved color image encoding and decryption. This breakthrough paves the way for thermally resilient metasurfaces for secure data encryption, anticounterfeiting, and robust operation in extreme environments.
Open Access
Strong coupling of double resonance designs and epsilon-near-zero modes for mode-matching enhancement of second-harmonic generation

October 23, 2025

Ai-Yin Liu, Chun-Hsiang Tseng, Kuang-I Lin, Hui-Hsin Hsiao

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We investigate the coupling effects between a double-resonance split-ring resonators (SRRs) design and the epsilon-near-zero (ENZ) guided mode of ultrathin indium tin oxide (ITO) films on second-harmonic generation (SHG). The optimized SRRs with an aspect ratio of 0.3 support a magnetic dipole (MD) resonance within the ENZ regime of ITO and a higher-order resonance at the SH frequency to achieve mode matching under cross-polarized excitation. The SRR-ITO coupled system (as opposed to the nanorod-ITO coupled system) was found to perform constructive (destructive) polarization interference between the nonlinear polarization currents at the upper hybridized modes (ω + ) and the linear electric field at SH frequency (2ω + ), resulting in a 1218-fold SHG enhancement outperformed than that of the nanorod-ITO coupled system, as predicted by overlap integral analysis. The measured SHG conversion efficiency for the SRR-ITO coupled system exceeds 10 −7 at an excitation wavelength of 1,320 nm, corresponding to a one-order (two-order) of magnitude enhancement compared to the nanorod-ITO coupled system (Au/ITO film). These findings highlight the potential of the proposed hybrid metasurfaces for efficient cross-polarized nonlinear signal generation, paving the way for advanced applications such as light sources, modulators in integrated photonic circuits, and biological sensing.
Open Access
Multicolor nanoring arrays with uniform and decoupled scattering for augmented reality displays

October 28, 2025

Inchul Woo, Hyeokjung Kang, Namkyoo Park

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For vivid, immersive overlay of virtual images onto background scenes in augmented reality (AR) applications, it is crucial for the display element to achieve controllability of spectral selectivity and transmittance level. At the current stage, the transmittance of self-emissive transparent displays is limited to at most ∼60 %, constrained by the fill factor of emissive regions, restricting their scalability for immersive experiences. Although projection-based transparent screens using frequency-selective scatterers offer a promising alternative, the platforms suffer from spectral broadening and instability originating from color-dependent scattering and inter-scatterer coupling. Here, we present a transparent screen architecture based on multicolor nanoring arrays. By tuning the nanoring’s resonance via inner-aperture size engineering, the architecture enables dense, symmetric RGB arrays with isolated and homogenized scattering responses. For inter-scatterer distances of 100–200+ nm, full-wave simulations confirm the robustness of well-isolated RGB reflections (FWHM < 25 nm), along with exceptional tunability of transmittance (50 % to above 80 %). As a platform for AR displays, we demonstrate the widest reported transparency-control range without any penalty to color balance or spectral selectivity. We also analyze the gamut area of projected images across transmittance levels, achieving a net gamut expansion (+11.0 % p at Λ = 120 nm; +5.5 % p at Λ = 190 nm) from the spectral narrowing of projection sources, and further propose a practical design map linking the maximum allowable transmittance to the ambient-to-source noise ratio. Our nanoring-based architecture provides a robust and scalable platform for next-generation transparent displays under real-world lighting conditions.
Open Access
Online training and pruning of multi-wavelength photonic neural networks

November 10, 2025

Jiawei Zhang, Weipeng Zhang, Tengji Xu, Lei Xu, Eli A. Doris, Bhavin J. Shastri, Chaoran Huang, Paul R. Prucnal

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CMOS-compatible photonic integrated circuits (PICs) are emerging as a promising platform in artificial intelligence (AI) computing. Owing to the compact footprint of microring resonators (MRRs) and the enhanced interconnect efficiency enabled by wavelength division multiplexing (WDM), MRR-based photonic neural networks (PNNs) are particularly promising for large-scale integration. However, the scalability and energy efficiency of such systems are fundamentally limited by the MRR resonance wavelength variations induced by fabrication process variations (FPVs) and environmental fluctuations. Existing solutions use post-fabrication approaches or thermo-optic tuning, incurring high control power and additional process complexity. In this work, we introduce an online training and pruning method that addresses this challenge, adapting to FPV-induced and thermally induced shifts in MRR resonance wavelength. By incorporating a power-aware pruning term into the conventional loss function, our approach simultaneously optimizes the PNN accuracy and the total power consumption for MRR tuning. In proof-of-concept on-chip experiments on the Iris dataset, our system PNNs can adaptively train to maintain above 90 % classification accuracy in a wide temperature range of 26–40 °C while achieving a 44.7 % reduction in tuning power via pruning. Additionally, our approach reduces the power consumption by orders-of-magnitude on larger datasets. By addressing chip-to-chip variation and minimizing power requirements, our approach significantly improves the scalability and energy efficiency of MRR-based integrated analog photonic processors, paving the way for large-scale PICs to enable versatile applications including neural networks, photonic switching, LiDAR, and radio-frequency beamforming.
Open Access
Heterogeneously-integrated lasers on thin film lithium niobate

November 28, 2025

Mingxiao Li, Chao Xiang, Joel Guo, Jonathan Peters, Mario Dumont, Shixin Xue, Jeremy Staffa, Qili Hu, Zhengdong Gao, Qiang Lin, John E. Bowers

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We demonstrate a versatile heterogeneous integration platform unifying III–V gain with thin-film lithium niobate (TFLN) photonic circuits to create high-performance lasers with integrated functionality. This breakthrough overcomes the critical barrier to fully integrated photonic systems by combining optical gain, low-loss cavities, and phase control on a single chip. We present two distinct laser architectures: a distributed feedback laser achieving 11.0 kHz intrinsic linewidth and 4.0 mW in-fiber power through self-injection locking to a high- Q TFLN resonator, and a Vernier ring laser exhibiting 44 nm continuous tuning range with > ${ >} $ 40 dB side-mode suppression ratio. Crucially, the heterogeneous integration of the gain section with TFLN’s components provides a promising path to implementing direct intracavity modulation, which is a functionality that typically requires discrete components. This inherent capability makes our platform a foundational advancement for future compact, robust systems in coherent communications, ultrafast optical metrology, quantum photonic processors, and microwave photonic systems operating at GHz bandwidths, marking a significant advancement toward complete photonic system integration.
Open Access
High-Q and compact Fabry–Perot microresonators on thin-film lithium niobate

October 21, 2025

Likai Yang, Chunzhen Li, Jiacheng Xie, Hong X. Tang

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Thin-film lithium niobate (TFLN) has played a pivotal role in the advancement of integrated photonics, by supporting a diverse range of applications including nonlinear optics, electro-optics, and piezo-optomechanics. The effective realization and enhancement of these interactions rely heavily on the implementation of high quality photonic microresonators. The pursuit of novel resonator architectures with optimized properties thus represents a central research area in TFLN photonics. In this work, we design and fabricate TFLN Fabry–Perot microresonators, by placing a straight section of waveguide between a pair of tapered photonic crystal mirrors. The resonator features a high quality factor of 6 × 10 5 at 1,530 nm and a compact length of 100 µm. The functionality of the device is further demonstrated by integrating on-chip electrodes for high-frequency piezo-optomechanical modulation. Our device can serve as an appealing candidate for developing high-performance photonic components on the TFLN platform.
Open Access
Structuring polarization states of light in space and time

November 20, 2025

Danilo Gomes Pires, Jiaren Tan, Hooman Barati Sedeh, Natalia M. Litchinitser

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The spatiotemporal sculpturing of light beams with arbitrary phase and polarization topologies has garnered significant attention in recent years due to its potential to advance optical technologies and reveal novel physical phenomena. Examples of spatiotemporal beams include space–time wave packets, flying donuts, tilted pulse fronts, X-waves, Airy pulses, and spatiotemporal optical vortices. Here, we introduce and demonstrate a new class of spatiotemporal polarization states of light. We propose a generalized spatiotemporal higher-order Poincaré sphere and show that these polarization states emerge from the superposition of two orthogonal circular polarization states, each carrying a spatiotemporal optical vortex. Such a choice of the basis enables simultaneous control of the spatial and temporal degrees of freedom of light. Theoretical predictions are experimentally validated using ultrafast femtosecond pulses, revealing how the resulting polarization distributions evolve in both space and time. Finally, we further extend this approach to construct a family of spatiotemporal skyrmionic textures that are localized, topologically nontrivial configurations of the electromagnetic field vector, offering a versatile framework for generating and controlling multidimensional (space and time) structured polarization fields. The ability to create and manipulate diverse forms of spatiotemporal skyrmionic textures opens up new opportunities for studying complex light–matter interaction phenomena, advanced imaging and micromanipulation, and encoding information across both space and time, with potential implications for advanced optical communication and information processing in classical and quantum domains.
Open Access
Goos–Hänchen effect singularities in transdimensional plasmonic films

September 18, 2025

Svend-Age Biehs, Igor V. Bondarev

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We identify and classify topologically protected singularities for the reflection coefficient of transdimensional plasmonic systems. Originating from nonlocal electromagnetic response due to vertical electron confinement in the system, such singularities lead to lateral (angular) Goos–Hänchen shifts on the millimeter (milliradian) scale in the visible range, greatly exceeding those reported previously for artificially designed metasurfaces, offering new opportunities for quantum material development.
Open Access
A 10× continuously zoomable metalens system with super-wide field of view and near-diffraction–limited resolution

November 24, 2025

Wangzhe Zhou, Shaoqi Li, Yiyi Li, Zongyuan Chen, Man Yuan, Fen Zhao, Yutai Chen, Huan Chen, Zhaojian Zhang, Jiagui Wu, Junbo Yang

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Moiré metalens is attractive for imaging applications due to their compact form factor and high zoom ratio. Here, we propose a novel Moiré zoom metalens system that achieves a continuous 10× zoom over a focal length range of 2.2–22 mm at 1,064 nm, while extending the full field of view up to 93°. A variable aperture, capable of axial translation, is introduced to jointly suppress aberrations and maintain a large aperture size with f-numbers ranging from 2.5 to 7.5. The system delivers near-diffraction–limited imaging resolution across the entire zoom and field-of-view range, with Strehl ratios exceeding 0.9. This level of performance is comparable to commercial optics and is rarely reported in metalens-based zoom systems. Remarkably, the total optical volume is only ∼4.2 × 32 mm, underscoring its potential for miniaturized imaging. Furthermore, we establish an integrated design and validation pipeline that strategically combines geometric optics, scalar diffraction, and vectorial electromagnetic theory. This multi-theory approach provides an efficient and generalizable pathway for the development of high-performance metalens systems.
Open Access
Beyond limits: a tribute to Dai-Sik Kim’s academic legacy and vision

October 16, 2025

Jae Sung Ahn, Kwang Jun Ahn, Young-Mi Bahk, Geunchang Choi, Jeeyoon Jeong, Young-Gyun Jeong, Taehee Kang, Hyun Woo Kim, Richard H.J. Kim, Sunghwan Kim, Dukhyung Lee, Geon Lee, Joong Wook Lee, Kwang-Geol Lee, Woongkyu Park

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This article is dedicated to the cherished memory of Prof. Dai-Sik Kim, a visionary leader and an inspiring mentor who profoundly shaped international as well as domestic landscape of optical science, and addresses topics that were central to his scientific passion in nanophotonics. Prof. Kim’s research spanned surface plasmonics, near-field optics, and terahertz plasmonics and spectroscopy, each reflecting his enduring commitment to exploring the interaction between light and matter beyond conventional limits.
Open Access
Segmented finger electrodes to optimize ultra-long continuous wafer-scale periodic poling in thin-film lithium niobate

December 1, 2025

Laura Bollmers, Noah Spiegelberg, Michael Rüsing, Christof Eigner, Laura Padberg, Christine Silberhorn

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Periodically poled thin-film lithium niobate (TFLN) crystals are the fundamental building block for highly-efficient quantum light sources and frequency converters. The efficiency of these devices is strongly dependent on the interaction length between the light and the nonlinear material, scaling quadratically with this parameter. Nevertheless, the fabrication of long, continuously poled areas in TFLN remains challenging, the length of continuously poled areas rarely exceeds 10 mm. In this work, we demonstrate a significant progress in this field achieving the periodic poling of continuous poled areas of 70 mm length with a 3 μm poling period and a close to 50 % duty cycle. We compare two poling electrode design approaches to fabricate long, continuous poled areas. The first approach involves the poling of a single, continuous 70 mm long electrode. The second utilize a segmented approach including the poling of more than 20 individual sections forming together a 70 mm long poling area with no stitching errors. While the continuous electrode allows for faster fabrication, the segmented approach allows to individually optimize the poling resulting in less duty cycle variation. A detailed analysis of the periodic poling results reveals that the results of both are consistent with previously reported poling outcomes for shorter devices. Thus, we demonstrate wafer-scale periodic poling exceeding chiplet-size without any loss in the periodic poling quality. Our work presents a key step towards highly-efficient, narrow-bandwidth and low-pump power nonlinear optical devices.
Open Access
Wafer-scale integration of photonic integrated circuits and atomic vapor cells

December 5, 2025

Arieh Grosman, Roy Zektzer, Noa Mazurski, Liron Stern, Uriel Levy

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Atom-based technologies have played a central role in both fundamental research and application-driven developments. For example, devices such as atomic clocks and magnetometers are essential for precision time-keeping, navigation, and sensing. However, many of these demonstrations remain confined to laboratory settings due to their reliance on bulky equipment and centimeter-scale atomic vapor cells. In recent years, significant efforts have been made to miniaturize these vapor cells to enable field-deployable systems. Yet, integrating these cells with the necessary photonic components remains a complex and non-scalable process. To address this challenge, we have introduced the atomic-cladded waveguide (ACWG) architecture, which enables the integration of atomic and photonic functions on the same chip. While the ACWG concept provides a significant step forward toward integration, there is still a significant gap related to wafer scale manufacturability. In particular, previous demonstrations of atomic–photonic integration have relied on manual assembly of vapor cells onto single chips, restricting miniaturization, manufacturability, and thermal robustness. To revolutionize manufacturability of these devices, we hereby demonstrate our new generation of ACWG devices that overcomes these constraints. The approach is based on wafer bonding of a silicon wafer – consisting of multiple photonic chips to a glass wafer with pre-etched atomic chambers. This wafer-scale process yields multiple miniaturized integrated photonic–atomic chips in a single batch. The bonded devices operate reliably at elevated temperatures over an extended period of time, allowing higher atomic densities to be used. The fabrication method consists of well-defined, repeatable steps, paving the way for scalable production of mature integrated photonic–atomic systems for next-generation sensing, metrology, and quantum technologies, inspired by commercial complementary metal-oxide-semiconductor-based processes.
Open Access
The longitudinal dynamics evolution of optical skyrmions via meta-optics

December 1, 2025

Tiantian He, Chang Liu, Wenxuan Tang, Dan Li, Ping Yan, Qiang Liu, Qirong Xiao

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Skyrmions, as topologically structured light fields, have attracted considerable attention due to their unique topological properties and potential applications such as optical communication and advanced sensing technologies. However, their longitudinal evolution, as a dimension ripe for exploitation, typically remains uncontrolled and non-deterministic, hindering its in-depth exploration and application scenarios. Here, this paper presents a novel method using dielectric metasurfaces for precisely modeling the longitudinal dynamics evolution of skyrmions. We introduce a new mechanism that allows for the accurate period modulation of skyrmions stokes properties along the propagation direction by controlling the differences in numerical apertures of a zero-order right-circularly polarized beam and a first-order left-circularly polarized beam. Crucially, the evolution period can be arbitrarily designed, and the propagation distance can be expanded by increasing the waist radius of input beams. To validate this approach, we showcase this paradigm through displacement sensing applications, where single-snapshot polarization measurements directly infer absolute position within a compact metasurface-integrated platform, offering a compact and simple alternative to conventional scanning-based approaches for displacement sensing. Our approach advances the understanding of dynamically controlled topological light fields and enables compact devices for precision metrology and optical information technologies.
Open Access
Rough Fabry–Perot cavity: a vastly multi-scale numerical problem

November 19, 2025

Tetiana Slipchenko, Jaime Abad-Arredondo, Antonio Consoli, Francisco J. García Vidal, Antonio I. Fernández-Domínguez, Pedro David García, Cefe López

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A commercial Fabry–Perot laser diode is characterized by highly disproportionate dimensions, which poses a significant numerical challenge, even for state-of-the-art tools. This challenge is exacerbated when one of the cavity mirrors is roughened, as is the case when fabricating random laser diodes. Such a system involves length scales from several hundred micrometres (length) to a few nanometres (roughness) all of which are relevant when studying optical properties in the visible. While involving an extreme range of dimensions, these cavities cannot be treated through statistical approaches such as those used with self-similar fractal structures known to show well-studied properties. Here we deploy numerical methods to compute cavity modes and show how random corrugations of the Fabry–Perot cavity wall affect statistical proper-ties of their spectral features. Our study constitutes a necessary first step in developing technologically essential devices for photonic computation and efficient speckle-free illumination.
Open Access
Tunable bound states in the continuum through hybridization of 1D and 2D metasurfaces

November 10, 2025

Fedor Kovalev, Mariusz Martyniuk, Andrey Miroshnichenko, Ilya Shadrivov

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This work presents a novel approach to create and dynamically control quasi-bound states in the continuum (BIC) resonances through the hybridization of 1D and 2D metasurfaces using micro-electromechanical systems (MEMS). The quasi-BIC resonance’s central wavelength and quality factor are precisely tuned by introducing out-of-plane symmetry breaking through a silicon MEMS membrane positioned above a 1D silicon metasurface. The proposed design achieves ultranarrow resonance linewidths with the spectral tuning range exceeding 60 nm while maintaining a constant quality factor. This tuning capability, realized through both horizontal displacement within a 1D metasurface and vertical MEMS membrane movement, offers a new degree of freedom for manipulating quasi-BIC resonances. The proposed hybridization of 2D and 1D metasurfaces using a MEMS mechanism provides a practical route to dynamic modulation of transmission resonance characteristics, making it a promising candidate for tunable filters, spectroscopy, imaging, and sensing applications.
Open Access
512 Gbps/λ dual-polarization thin-film lithium niobate modulators based on an electro-optic equalizer

November 25, 2025

Jianmin Zhang, Jian Shen, Shuxiao Wang, Zhuoyun Li, Wencheng Yue, Xin Ou, Yan Cai

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Driven by the development of AI applications, optical communication systems experience an exponential surge in the demand for high data rates. Thin-film lithium niobate (TFLN) electro-optic (EO) modulators have been extensively studied and show potential for application in next-generation optical communication systems. In this paper, we present a dual-polarization (DP) TFLN EO modulator integrated based on an EO equalizer, fabricated on the lithium-niobate-on-insulator (LNOI) platform. The device consists of an 11-mm-long forward modulation section and a 4.5-mm-long reverse modulation section. It achieves a half-wave voltage (V π ) of 4 V for both Y-polarization (Y-pol) and X-polarization (X-pol), and exhibits an on-chip insertion loss of 2.5 dB for Y-pol and 2.8 dB for X-pol at a wavelength of 1,550 nm. A 3-dB EO bandwidth exceeding 110 GHz with low EO roll-off is achieved for both TE and TM modes. Furthermore, the modulator supports a data transmission rate of 512 Gbit/s in 4-level pulse amplitude modulation (PAM4) format, corresponding to 256 Gbit/s per polarization. This work demonstrates a beyond 400 G/λ solution for implementing a high-speed, and large-bandwidth modulator on a conventional LNOI platform.
Open Access
Structured beam-driven multipolar mode control in nanoparticles

November 20, 2025

Asma Fallah, Eileen Otte

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Due to their unique tight focusing properties, structured light beams, such as cylindrical vector beams, offer unique opportunities for tailoring light–matter interaction at the nanoscale. In this work, we investigate the scattering response of a spherical nanoparticle illuminated by a Focused Generalized Cylindrical Vector Beam (FGCVB). We employ a full vectorial framework – numerically and analytically. We model the focal field distribution of the FGCVB, compute and examine the scattered fields using generalized Lorenz–Mie theory, and analyze the influence of beam polarization structure on the scattering cross section and multipole content of the scattered fields. We find that tailoring the polarization composition of the incident FGCVB allows selective excitation of and tuning between electric and magnetic dipolar as well as quadrupolar modes, which offers a pathway for polarization-controlled light scattering at the nanoscale. We also examine and employ the influence of focal point position and numerical aperture of the lens on the scattered field. This work expands our understanding of vector beam scattering and provides design principles for polarization-resolved nano-optical spectroscopy and microscopy.
Open Access
Large-scale silicon photonics switches for AI/ML interconnections based on a 300-mm CMOS pilot line

November 24, 2025

Keijiro Suzuki, Ryotaro Konoike, Siim Heinsalu, Shu Namiki, Hitoshi Kawashima, Kazuhiro Ikeda

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Silicon photonics switches are emerging as a key technology for realizing energy-efficient networks, spanning from intra data center to wafer-scale interconnections. This review focuses on recent developments and prospects of silicon photonics switches operating in the O-band, which is widely used in computing networks designed for artificial intelligence and machine learning applications. We first review our recent works on O-band silicon photonics switches fabricated by 300-mm silicon photonics technology. Specifically, we have expanded the port count of our O-band switches from 8 × 8 to 32 × 32 implemented with double Mach–Zehnder switch elements for a broad operating bandwidth. This switch achieved a 70-nm bandwidth for a crosstalk of less than −20 dB, and an average on-chip loss of 11.8 dB. Next, we discuss switch topologies optimized for wafer-scale interconnection. Conventional switch topologies typically have their input and output ports at opposite ends of the switch matrix, respectively, which poses challenges of long propagation distances and many waveguide intersections for off-chip planar waveguide routing to connect xPUs on substrate. To address this, we propose a topology where input and output ports are placed adjacently. An O-band 8 × 8 switch based on this topology was fabricated and experimentally demonstrated. Finally, we discuss the prospects and challenges of silicon photonic switches. Key issues include insertion loss, switching speed, crosstalk and operating bandwidth, and polarization dependence. These aspects are examined with reference to reports from other research groups, highlighting both current limitations and potential directions for further improvement.
Open Access
Density-functional tight binding meets Maxwell: unraveling the mysteries of (strong) light–matter coupling efficiently

November 26, 2025

Dominik Sidler, Carlos M. Bustamante, Franco P. Bonafé, Michael Ruggenthaler, Maxim Sukharev, Angel Rubio

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Controlling chemical and material properties through strong light–matter coupling in optical cavities has gained considerable attention over the past decade. However, the underlying mechanisms remain insufficiently understood, and a significant gap persists between experimental observations and theoretical descriptions. This challenge arises from the intrinsically multiscale nature of the problem, where nonperturbative feedback occurs across different spatial and temporal scales. Collective coupling between a macroscopic ensemble of molecules and a photonic environment, such as a Fabry–Pérot cavity, can strongly influence the microscopic properties of individual molecules, while microscopic details of the ensemble in turn affect the macroscopic coupling. To address this complexity, we present an efficient computational framework that combines density-functional tight binding (density-functional tight binding ( dftb )) with finite-difference time-domain (finite-difference time domain ( fdtd )) simulations of Maxwell’s equations ( dftb + Maxwell). This approach allows for a self-consistent treatment of both the cavity and the microscopic details of the molecular ensemble. We demonstrate the potential of this method by tackling several open questions. First, we calculate nonperturbatively two-dimensional spectroscopic observables that directly connect to well-established experimental protocols. Second, we provide local, molecule-resolved information within collectively coupled ensembles, which is difficult to obtain experimentally. Third, we show how cavity designs can be optimized to target specific microscopic applications. Finally, we outline future directions to enhance the predictive power of this framework, including extensions to finite temperature, condensed phases, and correlated quantum effects. The dftb + Maxwell method enables real-time exploration of realistic chemical parameters on standard computational resources and offers a systematic approach to bridging the gap between experiment and theory.
Open Access
Vortex beam nanofocusing and optical skyrmion generation via hyperbolic metamaterials

September 18, 2025

Wenhao Li, Jacob LaMountain, Evan Simmons, Jiaren Tan, Hooman Barati Sedeh, Anthony Clabeau, Robel Y. Bekele, Jason D. Myers, Takashige Omatsu, Jesse Frantz, Viktor A. Podolskiy, Natalia M. Litchinitser

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While spin angular momentum is limited to ± ℏ , orbital angular momentum (OAM) is, in principle, unbounded, enabling tailored optical transition rules in quantum systems. However, the large optical size of vortex beams hinders their coupling to nanoscale platforms such as quantum emitters. To address this challenge, we experimentally demonstrate the subdiffraction focusing of an OAM-carrying beam using a hypergrating, a flat meta-structure based on a multilayered hyperbolic composite. We show that our structure generates and guides high-wave vector modes to a deeply subwavelength spot and experimentally demonstrate the focus of an OAM-carrying beam on a spot size of ∼ λ /3. We also show how the proposed platform facilitates the formation of an optical skyrmion with spin textures as small as λ /250, opening new avenues for controlling light–matter interactions.
Open Access
Dual-state six-channel polarization multiplexing in reconfigurable metasurfaces

November 10, 2025

Sujun Xie, Tianxu Jia, Xiaoyue Ma, Bingjue Li, Ruohu Zhang, Zhigang Li, Binfeng Yun, Hyeonsu Heo, Nara Jeon, Guanghao Rui, Junsuk Rho

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Dynamically tunable metasurfaces based on phase-change materials (PCMs) have become important platforms for realizing reconfigurable optical systems. Nevertheless, achieving multiple independent functionalities within a single device, particularly under polarization multiplexing, remains difficult due to limited design flexibility. In this study, we present a metasurface design framework that reaches the theoretical maximum of six independent phase modulation functions by simultaneously controlling the polarization states and the crystallinity of the PCM. This is implemented through a pixel-extension strategy, where each nanofin functions independently in amorphous state and is reorganized into superpixels with distinct optical responses in crystalline state. To support this, a forward filtering algorithm is developed to efficiently determine structural configurations under dual-state constraints. The effectiveness of the proposed approach is confirmed through two representative implementations, including dynamically switchable multifocal metalenses and multichannel holography. In addition, a progressive encoding strategy is introduced, which deliberately utilizes inter-state crosstalk to hierarchically embed optical information across material states. This compact and reconfigurable metasurface platform offers high functional density and flexible control, holding strong potential for applications in optical communication, information encryption, and adaptive display technologies.
Open Access
Single-shot Stokes polarimetry of plasmon-coupled single-molecule fluorescence

November 6, 2025

Sarojini Mahajan, Yuyang Wang, Teun A.P.M. Huijben, Rodolphe Marie, Peter Zijlstra

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The photophysical properties of single-molecule emitters are altered by nanophotonic structures such as single plasmonic nanoparticles. The intensity and spectral properties of plasmon-coupled emitters have been studied extensively, but little is known about the effect of plasmon coupling on emission polarization. Here, we examine how particle-emitter coupling modifies the polarization of single fluorophores in both experiment and simulation. We quantify degree of linear polarization using Stokes polarimetry with a polarization-sensitive camera and quantify the Stokes parameters with a single-shot acquisition without requiring additional optics in the detection path. We then perform polarization-resolved measurements of plasmon-coupled fluorescence from single-molecule emitters using an approach based on DNA-PAINT. We quantify the effect of the setup and associated noise sources on the measured Stokes parameters. We then quantify the angle of linear polarization (AoLP) and the degree of linear polarization (DoLP) for thousands of single molecules. We compare our results to a numerical model that propagates the plasmon-coupled single-molecule emission through the optical setup to yield the polarized point spread function in the camera plane. Simulations and experiments are in good agreement and shed new light on the polarization of antenna-coupled fluorophores, while it establishes single-shot polarimetry as a promising and straightforward method to quantify polarization properties at the single-molecule level.
Open Access
Directional enhancement of photoluminescence from phosphor plates with TiO₂ nanoantenna stickers

December 1, 2025

Hongjie Gao, Joshua T.Y. Tse, Shunsuke Murai, Katsuhisa Tanaka

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Directional illumination is critical for next-generation solid-state lighting. In this study, we demonstrate that flexible nanoantenna stickers enhance photoluminescence (PL) directionality. By integrating YAG:Ce phosphor plates and distributed Bragg reflectors (DBRs), these stickers achieve controlled radiation distribution, advancing the development of compact, high-performance illumination technologies. In addition, these stickers produce a different PL output by simply changing the thickness of the phosphor plate. The output PL intensity is doubled by placing a DBR layer on the bottom of the plate, thereby transmitting blue excitation light while reflecting yellow PL. This study provides a simple and versatile method for tuning PL from phosphor plates. This technique can serve as a fundamental tool for controlling light flow with improved efficiency.
Open Access
Optical see-through augmented reality via inverse-designed waveguide couplers

December 8, 2025

Seunghyun Lee, Byounghyo Lee, Haejun Chung

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Waveguide-based augmented-reality (AR) displays offer compact, optical see-through form factors but remain limited by chromatic dispersion, ghosting from parasitic diffraction orders, distortion of the see-through scene, and a restricted eyebox. We present triple-function metasurface couplers designed using adjoint-based optimization, which overcome these limitations and establish computational performance bounds. The out-coupler simultaneously preserves zeroth-order transmission of the see-through path and directs display light into designated diffraction orders while returning residual guided power as zeroth-order reflection for eyebox expansion. The in-coupler assigns distinct diffraction orders to R/G/B and equalizes their in-plane propagation angles, achieving achromatic guidance and eliminating chromatic path divergence. Quantitatively, the optimized out-coupler provides >90 % angle-averaged zeroth-order transmission for the see-through view (10–40× lower higher-order leakage) and >95 % zeroth-order guided reflection, while maintaining efficient diffractive couplings to the eyebox. PSF/MTF analyses confirm near-diffraction-limited virtual-image quality and strong suppression of see-through view distortion. Finally, benchmarking freeform against fabrication-constrained multilayer architectures (1–6 layers) shows that multilayers approach the freeform upper bound while remaining practical to fabricate. These results outline a general, manufacturable methodology for multifunctional metasurface couplers and a practical route to compact, high-quality AR waveguides.
Open Access
Dual-band spectral filter array integrated with a telecentric lens for real-time surface plasmon resonance sensing and imaging

December 5, 2025

Yi-Hsin Tai, Chih-Hung Kuo, Shenq-Hann Wang, Xiu-Wan Chen, Hsin-Yi Hsieh, Chia-Chun Chang, Pei-Kuen Wei, Chin-Chuan Hsieh

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Multispectral and hyperspectral imaging have been extensively applied in various imaging domains, where spectral channels with narrow bandwidths provide detailed information for optical signal analysis. The integration of multi-channel filter arrays with image sensors is essential for multispectral detection. To extend this capability to cameras without integrated filters, a dual-band spectral filter array (DSFA) combined with a telecentric lens was employed with a monochrome camera for real-time surface plasmon resonance imaging (SPRi). Placement of the DSFA in front of a broadband light source generated spatially modulated excitation signals incident on a gold-coated periodic silicon nanostructure serving as a surface plasmon resonance (SPR) chip. A pixel-shift-based demosaicing method enabled the separation of checkerboard-like images into two spectral bands corresponding to the filters of the DSFA, facilitating γ -based spectral contrast response analysis. This optical configuration successfully demonstrated dynamic monitoring of the interaction between anti-BSA and immobilized BSA on the chip. Compared with wavelength-shift analysis, γ -based analysis improved the refractive index detection limit by nearly two orders of magnitude, enabling highly sensitive monitoring of biomolecular interactions. The DSFA-based SPRi platform provides a flexible, highly integrable, and label-free solution for quantitative analysis of biomolecular interactions.
Open Access
Sub-100 nm manipulation of blue light over a large field of view using Si nanolens array

November 25, 2025

Zhiyuan Shi, Wei Jiang, Yanqing Lu, Weihua Zhang

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This study presents a super-resolution light manipulation technique in the near-field region of a silicon nanolens array in the blue spectral range using a computer-generated holography technique. It allows us to focus light into a spot below 70 nm at arbitrarily given positions within the entire lens array using modulated incident fields. To achieve this, an inverse design algorithm is developed using multiaxis high-order Gaussian beam expansion. It effectively corrects aberrations in off-axis focal spots within each nanolens unit, resulting in high-quality nanofocused beams with an extended depth of focus. By superimposing discrete nanofocused spots, we can further synthesize complex intensity patterns across multiple nanolens units, achieving an intensity profile resolution of 80 nm. This offers a promising approach for super-resolution photolithography using visible light.
Open Access
On-chip polarization management for stable nonlinear signal generation in thin-film lithium niobate

November 10, 2025

Junhyung Lee, Sunghyun Moon, Yongchan Park, Uijoon Park, Hansol Kim, Changhyun Kim, Minho Choi, Jin-Il Lee, Hyeon Hwang, Min-Kyo Seo, Dae-Hwan Ahn, Hojoong Jung, Hyounghan Kwon

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Nonlinear signal generation requires precise control of the input polarization to satisfy phase-matching conditions. Conventional polarization management using external fiber polarization controllers or bulk wave plates increases coupling complexity and can degrade polarization fidelity and conversion efficiency in nonlinear photonic systems. Here, we demonstrate on-chip polarization control in thin-film lithium niobate nonlinear photonic circuits. Integrated polarization modulators enable real-time tuning of arbitrary input polarization states and thus provide on-demand control of nonlinear conversion in a periodically poled lithium niobate waveguide. A closed-loop feedback system, which integrates auto-compensation and automatic fiber-chip alignment routines, automatically optimizes the second-harmonic generation intensity and maintains performance over extended periods despite polarization scrambling and environmental perturbations. This integrated approach reduces coupling complexity and offers a scalable route toward fully reconfigurable nonlinear photonic systems.
Open Access
Bright single-photon skyrmion sources in bullseye cavities

November 10, 2025

Jiantao Ma, Shunfa Liu, Chengjie Lu, Ying Yu, Bo Chen, Jin Liu

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Optical skyrmions, as structured light fields endowed with discrete topological numbers, open new opportunities for high-density encoding, robust information transport, and quantum light–matter interactions. However, most existing skyrmion generators rely on complex or bulky systems, hindering their application in scalable on-chip quantum technologies. Here, we propose a nanophotonic scheme based on semiconductor cavity quantum electrodynamics, whereby a circularly polarized quantum emitter is coupled to a concentric bullseye resonator. This configuration enables the efficient generation of single-photon Stokes vector skyrmions at subwavelength scales, as well as their high-order extensions. By exciting single-photon sources at different positions, the skyrmion number can be continuously switched between +2 and −2, while higher-order states are accessible by tuning the radius of cavity’s center disc. This strategy couples the topological dimension of skyrmions with quantum states, laying the groundwork for quantum skyrmions in on-chip topological keying and quantum readout. Our work provides a practical device architecture for integrated nanophotonic quantum topological state platforms, offering a new paradigm for topologically protected quantum communications and on-chip quantum information processing.

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Issue 23

Special Issue: In Honor of Federico Capasso, A Visionary in Nanophotonics

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Special Issue: Quantum Cascade Laser: 30 Years of Discoveries

Special Issue: Guided Nonlinear Optics for Information Processing

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Special Issue: Metamaterials and Plasmonics in Asia

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Special Issue: Spatiotemporal Optical Fields

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Special Issue: Programmable Nano-optics and Photonics

Issue 11

Special Issue: Nanophotonics out of Equilibrium

Issue 10

Special Issue: Infrared and Terahertz Quantum Technologies

Issue 9

Issue 8

Special Issue: Metamaterials and Plasmonics in Asia

Issue 7

Special Issue: New Frontiers of Nanophotonics through Metamaterials, Photonic Crystals, and Plasmonics

Issue 6

Issue 5

Special Issue: Thermal Photonics for Sustainability

Special Issue: Nanophotonics in support of Ukrainian Scientists

Issue 13

Special Issue: Metamaterials and plasmonics in Asia, a tribute to Byoungho Lee

Special Issue: Nanofabrication

Issue 7

Issue 6

Issue 5

Special Issue: Neural network learning with photonics and for photonic circuit design

Issue 4

Issue 3

Special Issue: Quantum Nanophotonics

Issue 2

Issue 1

Issue 22

Special Issue: Novel Two-Dimensional Materials Based Bio-Nanophotonic

Special Issue: Tunable Nanophotonics

Special Issue: New Trends in Nanophotonics and Advanced Photonic Materials

Issue 10

Issue 9

Special Issue: Metamaterials and Plasmonics in Asia

Special Issue: Photonic Angular Momentum

Special Issue: Nonradiating photonics with resonant dielectric nanostructures

Issue 16

Issue 15

Issue 14

Special Issue: Honorary Issue for Mark Stockman

Issue 13

Issue 12

Special Issue: Nanophotonics and immunotherapy for cancer; Guest Editors: Feifan Zhou, Tayyaba Hasan, Celine Frochot, Wei R. Chen

Special Issue: Photonics for Enhanced Perovskite Optoelectronics; Guest Editors: Hairen Tan, Li Na Quan and Michael Saliba

Special Issue: Frontiers of Optics and Photonics; Guest Editors: Federico Capasso and Dennis Couwenberg

Special Issue: Photonics for Computing and Computing for Photonics, Guest Editors: Daniel Brunner, Aydogan Ozcan, Alireza Marandi, Wim Bogaerts

Issue 12

Special Issue: Interdisciplinary Nanophotonics; Guest Editors: Hatice Altug, Laura Na Liu

Issue 11

Issue 10

Special Issue: Metamaterials and Plasmonics in Asia; Guest Editors: Jeong Weon Wu, Teruya Ishihara, Lei Zhou, Cheng-Wei Qiu

Issue 9

Issue 8

Special Issue: 2D materials for nanophotonics: from fundamentals to applications, II. Applications; Guest Editors: Xiantao Jiang, Meng Zhang, Xi Ling, Pablo Alonso González, Han Zhang

Issue 7

Special Issue: 2D materials for nanophotonics: from fundamentals to applications, I. Fundamentals; Guest Editors: Xiantao Jiang, Meng Zhang, Xi Ling, Pablo Alonso González, Han Zhang

Issue 6

Issue 5

Special Issue: New trends in nanophotonics; Guest Editors: Sunae So, Namkyoo Park, Hak Joo Lee, Junsuk Rho

Issue 4

Issue 3

Issue 2

Special Issue: Proceedings of Surface Plasmon Photonics Conference (SPP9); Guest Editors: N. Asger Mortensen, Pierre Berini, Uriel Levy, Sergey Bozhevolnyi

Issue 1

Issue 12

Issue 11

Special Issue: Quantum Nanophotonics in Emerging Materials; Guest Editors: A. Alkauskas, L. C. Bassett; A. L. Exarhos; Kai-Mei Fu

Issue 10

Issue 9

Special Issue: Interdisciplinary Nanophotonics; Guest Editors: E. Di Fabrizio and M. Stockman

Issue 8

Special Issue: Topological Nanophotonics; Guest Editors: Niels Asger Mortensen, Sergey I. Bozhevolnyi, Andrea Alù

Special Issue: Plasmon-Exciton Coupling; Guest Editors: Matthew Pelton, Matthew Sheldon, and Jacob Khurgin

Honorary issue for Federico Capasso on “Metamaterials & Metasurfaces”

Special Issue: 2D Materials

Issue 5

Issue 4

Special Issue: Optical Bio Sensors

Issue 3

Special Issue: Optical Computing

Special Issue: Quantum Photonics

Issue 2

Special Issue: Frequency Comb Generation

Issue 1

Special Issue: Smart Nanophotonics for Renewable Energy and Sustainability / Guest Editors: Alexander V. Kildishev, Svetlana Boriskina and Vivian Ferry

Issue 4

Issue 3

Issue 2

Special Issue: Emerging Materials for Nanophotonics / Guest Editors: Jenifer Dionne, Alexandra Boltasseva and Luke Sweatlock

Issue 1

Issue 6

Issue 4-5

Special issue: Silicon Photonic Integrated Devices / Guest Editors: Chris Doerr, Haisheng Rong and Michal Lipson

Issue 3

Issue 1-2

Special Issue: Near-field Optics: Generality in Super-Resolution Imaging in 3D \ Guest Editor: Aaron Lewis

Issue 5-6

Special Issue: Fiber Optic Nanotechnology / Guest Editors: Ming-Jun Li, David J. DiGiovanni, Alan E. Willner

Nanophotonics publishes special and thematic issues focussed on important and emerging topics in the field of study. The journal has established a rigorous process to ensure that any special issue manuscripts follow the same high-quality standards and peer review processes as regular manuscripts. For further information on the journal’s peer review policy please see the "Instructions for Authors".

Recent Special Issues

Journal Impact Factor	6.6	2024, Journal Citation Reports (Clarivate, 2025)
5-year Journal Impact Factor	7.3	2024, Journal Citation Reports (Clarivate, 2025)
Journal Citation Indicator	1.13	2024, Journal Citation Reports (Clarivate, 2025)
CiteScore	12.1	2024, Scopus (Elsevier B.V., 2025)
SCImago Journal Rank	1.765	2024, SJR (Scimago Lab, 2025; Data Source: Scopus)
Source Normalized Impact per Paper	1.686	2024, CWTS Journal Indicators (CWTS B.V., 2025; Data Source: Scopus)

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Submission

From 1 October 2025, the journal will transition to a new publisher. Please submit all manuscripts through the new submission site: https://submission.wiley.com/journal/NAP2 .

You can find more information on the new Journal Homepage.

FOUNDING EDITOR
Federico Capasso, Harvard University, USA

EDITOR IN CHIEF
Stefan Maier, Monash University, Australia
Email: stefan.maier@monash.edu

PUBLISHING EDITOR
Dennis Couwenberg, Science Wise Publishing, The Netherlands
Email: dcouwenberg@nanophotonics-journal.com

MANAGING EDITORS
Antonio I. Fernández-Domínguez, Universidad Autonoma de Madrid, Spain
Dangyuan Lei, City University of Hong Kong, Hong Kong, China
Yongmin Liu, Northeastern University College of Engineering, USA
Junsuk Rho, Pohang University of Science and Technology, Korea
Matthew Sheldon, University of California, Irvine, USA
Giulia Tagliabue, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Kiyoul Yang, Harvard University, USA

EDITORIAL ADVISORY BOARD
Javier Garcia de Abajo, IQFR-CSIC, Spain
Andrea Alu, City University of New York, USA
Dimitri Basov, Columbia University, USA
Mark Brongersma, Stanford University, USA
Jennifer Dionne, Stanford University, USA
Nader Engheta, University of Pennsylvania, USA
Shaya Fainman, UC San Diego, USA
Shanhui Fan, Stanford University, USA
Harald Giessen, University of Stuttgart, Germany
Michael Hochberg, University of Washington, USA
Frank Koppens, ICFO, Spain
Uriel Levy, The Hebrew University of Jerusalem, Israel
Michal Lipson, Cornell University, USA
Tony Low, University of Minnesota, USA
Asger Mortensen, DKU, Denmark
Evgenii Narimanov, Purdue University, USA
Masaya Notomi, NTT Basic Research Laboratories, Japan
Rupert Oulton, Imperial College London, UK
Aydogan Ozcan, UCLA, USA
Romain Quidant, ICFO, Spain
Vladimir Shalaev, Purdue University, USA
Volker Sorger, University of Florida, USA (Editor-in-Chief, 2015-2020)
Takuo Tanaka, RIKEN, Japan
Jelena Vuckovic, Stanford University, USA
Hongxing Xu, Wuhan University, China
Anatoly Zayats, King’s College London, UK
Xiang Zhang, UC Berkeley, USA
Nikolay Zheludev, University of Southampton, UK

Journal Coordinator
Justyna Zuk, De Gruyter
E-mail: nanophotonics.editorial@degruyter.com

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Topics

Technology Electrical Engineering Sensor Technology

Materials Sciences Nanomaterials and Nanotechnology

Physics Nanotechnology

Physics Electromagnetism, Optics and Photonics

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Journal information

Additional information

eISSN:

2192-8614

Language:

English

Publisher:

De Gruyter

Additional information

First published:

February 1, 2012

Publication Frequency:

24 issues per year

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eISSN: 2192-8614

Audience(s) for this journal

Physicists, Engineers and Material Scientists, in public and private research.

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