Abstract
In this brief opinionated article, I present a personal perspective on metamterials with high degrees of freedom and dimensionality and discuss their potential roles in enriching light–matter interaction in photonics and related fields.
1 Main text
To control and manipulate photons we often use materials. The light–matter interaction, which is at the heart of optics and photonics, is governed by the laws of electrodynamics, both classical as well as quantum electrodynamics. In dealing with electromagnetic wave and field interaction with materials, one can always start at the quantum level where photons interact with atoms. However, we often prefer to parameterize such interaction and consequently we commonly use the notion of macroscopic light–matter interaction, in which we assign certain material parameters to media with which waves and fields interact. Such electromagnetic parameters are well known quantities, such as permittivity
To achieve desired functionality from light–matter interaction, we often utilize spatial inhomogeneities in material parameters. For example, a simple convex lens operates based on the light propagation from air to the lens, formed by a material with
Although in the Maxwellian electrodynamics there are symmetries between space
Clearly, 4D metamaterials have brought, and continue to bring, various exciting new phenomena into the realm of light–matter interaction. But can we have 4D metamterials with more variables and higher degrees of freedom? Adding additional degrees of freedom can bring more novelty in controlling the wave phenemona using such structures. One possible way to do so is by merging temporal variation of the materials parameters, e.g.,
Although in the above discussion, we mentioned the 4D structures with high degrees of freedom based only on one of the material parameters, namely the permittivity, obviously this methodology can also be applied to other material parameters such as, permeability
To summarize, in my opinion it seems that increasing degrees of freedom in spatiotemporal metamaterials, while adds more complexity to the structures, can open new directions in research in light–matter interaction, with the goals towards devices and systems with new functionalities. Such possibilities are limitless.
Funding source: Office of Naval Research
Award Identifier / Grant number: N00014-16-1-2029
Funding source: US Air Force Office of Scientific Research
Funding source: Multidisciplinary University Research Initiative
Award Identifier / Grant number: FA9550-17-1-0002
Acknowledgments
The author acknowledges the partial support from the Vannevar Bush Faculty Fellowship program sponsored by the Basic Research Office of the Assistant Secretary of Defense for Research and Engineering, funded by the Office of Naval Research through grant N00014-16-1-2029, and the partial support from the US Air Force Office of Scientific Research (AFOSR) Multidisciplinary University Research Initiative (MURI) grant number FA9550-17-1-0002.
Author contribution: The author has accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: This research was funded partially by the Office of Naval Research through grant N00014-16-1-2029, and partially by the US Air Force Office of Scientific Research (AFOSR) Multidisciplinary University Research Initiative (MURI) grant number FA9550-17-1-0002.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
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© 2020 Nader Engheta, published by De Gruyter, Berlin/Boston
This work is licensed under the Creative Commons Attribution 4.0 International License.
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