Adaptive optical beam shaping for compensating projection-induced focus deformation

Oliver Pütsch; Jochen Stollenwerk; Peter Loosen

doi:10.1515/aot-2015-0055

Article

Adaptive optical beam shaping for compensating projection-induced focus deformation

Oliver Pütsch
Oliver Pütsch received his diploma in mechatronics engineering from Aachen University of Applied Sciences, Germany in 2008 and MSc in mechatronics in 2010. During his master course Oliver Pütsch worked at the faculty of mechanical engineering and mechatronics at Aachen University of Applied Sciences in the subject area of micro technology. He is currently pursuing a PhD in engineering and has been working as a research scientist at the Chair for Technology of Optical Systems at RWTH Aachen University since 2011. His research interests are the application and development of active and controlled optical devices.
, Jochen Stollenwerk
Jochen Stollenwerk received his Diploma degree in Physics at the RWTH Aachen University in 1996. He was a scientific employee at the Fraunhofer Institute for Laser Technology (ILT) and received his PhD in the area of laser material processing in 2001. In the same year he became Manager Application at TRUMPF Laser Marking Systems, Grüsch, Switzerland. In 2004 he became Vice Director at the newly founded Chair for the Technology of Optical Systems at RWTH Aachen University and Head of the Research Group “Thin Film Laser Processing” at the ILT. The research and teaching activities of Jochen Stollenwerk are concentrated on advanced optical systems for laser and laser systems as well as for lighting applications, EUV technology and on laser material processing.
and Peter Loosen
Peter Loosen received his Diploma degree at the Technical University of Darmstadt in the field of lasers for industrial manufacturing in 1980. He was a scientific employee at the Institute of Applied Physics of the Technical University of Darmstadt and received his PhD in the working group of Professor Herziger in the area of “High-Power CO2-Laser with Axial Gas Flow” in 1984. After his PhD-examination he moved to the newly founded Fraunhofer-Institute for Laser Technology in Aachen (ILT) in 1985, where he was responsible for the department “Gas Laser”. In 1989 he additionally took over the responsibility for the departments Solid-state Lasers, Metrology and Plasma Systems of the Fraunhofer-Institute. Since 1993 he has been the deputy head of the ILT and was appointed the Professor for “Technology of Optical Systems” and head of the newly formed respective institute at the RWTH-Aachen in 2004. The research and teaching activities of Peter Loosen are concentrated on the fundamentals and the technology of lasers and laser systems for industrial manufacturing and on optical systems for laser and laser systems. He has made considerable contributions in the fields of industrial high-power gas-, solid-state and diode lasers and the integration of such lasers into production applications.

Published/Copyright: February 17, 2016

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From the journal Advanced Optical Technologies Volume 5 Issue 1

Abstract

Scanner-based applications are already widely used for the processing of surfaces, as they allow for highly dynamic deflection of the laser beam. Particularly, the processing of three-dimensional surfaces with laser radiation initiates the development of highly innovative manufacturing techniques. Unfortunately, the focused laser beam suffers from deformation caused by the involved projection mechanisms. The degree of deformation is field variant and depends on both the surface geometry and the working position of the laser beam. Depending on the process sensitivity, the deformation affects the process quality, which motivates a method of compensation. Current approaches are based on a local adaption of the laser power to maintain constant intensity within the interaction zone. For advanced manufacturing, this approach is insufficient, as the residual deformation of the initial circular laser spot is not taken into account. In this paper, an alternative approach is discussed. Additional beam-shaping devices are integrated between the laser source and the scanner, and allow for an in situ compensation to ensure a field-invariant circular focus spot within the interaction zone. Beyond the optical design, the approach is challenging with respect to the control theory’s point of view, as both the beam deflection and the compensation have to be synchronized.

Keywords: active and adaptive optics; beam shaping; laser materials processing

Corresponding author: Oliver Pütsch, Chair for Technology of Optical Systems (TOS), RWTH Aachen University, Aachen, Germany, e-mail: oliver.puetsch@tos.rwth-aachen.de

About the authors

Oliver Pütsch

Oliver Pütsch received his diploma in mechatronics engineering from Aachen University of Applied Sciences, Germany in 2008 and MSc in mechatronics in 2010. During his master course Oliver Pütsch worked at the faculty of mechanical engineering and mechatronics at Aachen University of Applied Sciences in the subject area of micro technology. He is currently pursuing a PhD in engineering and has been working as a research scientist at the Chair for Technology of Optical Systems at RWTH Aachen University since 2011. His research interests are the application and development of active and controlled optical devices.

Jochen Stollenwerk

Jochen Stollenwerk received his Diploma degree in Physics at the RWTH Aachen University in 1996. He was a scientific employee at the Fraunhofer Institute for Laser Technology (ILT) and received his PhD in the area of laser material processing in 2001. In the same year he became Manager Application at TRUMPF Laser Marking Systems, Grüsch, Switzerland. In 2004 he became Vice Director at the newly founded Chair for the Technology of Optical Systems at RWTH Aachen University and Head of the Research Group “Thin Film Laser Processing” at the ILT. The research and teaching activities of Jochen Stollenwerk are concentrated on advanced optical systems for laser and laser systems as well as for lighting applications, EUV technology and on laser material processing.

Peter Loosen

Peter Loosen received his Diploma degree at the Technical University of Darmstadt in the field of lasers for industrial manufacturing in 1980. He was a scientific employee at the Institute of Applied Physics of the Technical University of Darmstadt and received his PhD in the working group of Professor Herziger in the area of “High-Power CO2-Laser with Axial Gas Flow” in 1984. After his PhD-examination he moved to the newly founded Fraunhofer-Institute for Laser Technology in Aachen (ILT) in 1985, where he was responsible for the department “Gas Laser”. In 1989 he additionally took over the responsibility for the departments Solid-state Lasers, Metrology and Plasma Systems of the Fraunhofer-Institute. Since 1993 he has been the deputy head of the ILT and was appointed the Professor for “Technology of Optical Systems” and head of the newly formed respective institute at the RWTH-Aachen in 2004. The research and teaching activities of Peter Loosen are concentrated on the fundamentals and the technology of lasers and laser systems for industrial manufacturing and on optical systems for laser and laser systems. He has made considerable contributions in the fields of industrial high-power gas-, solid-state and diode lasers and the integration of such lasers into production applications.

Acknowledgments

The authors would like to thank the Volkswagen Foundation for the financial support (Funding Initiative I/83252) with the project title ‘Shaping of Functional and Design Surfaces by Laser Remelting (WaveShape)’, and also the German Research Foundation (DFG) for the support within the Cluster of Excellence ‘Integrative Production Technology in High-Wage Countries’ at RWTH Aachen University. The above results were acquired using facilities and devices funded by the Federal State of North-Rhine Westphalia within the Center for Nanophotonics under grant number 290047022.

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Received: 2015-11-23

Accepted: 2016-1-14

Published Online: 2016-2-17

Published in Print: 2016-2-1

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Articles in the same Issue

https://doi.org/10.1515/aot-2015-0055

Keywords for this article

active and adaptive optics; beam shaping; laser materials processing