3D-patterned inverse-designed mid-infrared metaoptics
Modern imaging systems can be enhanced in efficiency, compactness, and application through the introduction of multilayer nanopatterned structures for manipulation of light based on its fundamental properties. High transmission multispectral imaging is elusive due to the commonplace use of filter arrays which discard most of the incident light. Further, given the challenges of miniaturizing optical systems, most cameras do not leverage the wealth of information in polarization and spatial degrees of freedom. Optical metamaterials can respond to these electromagnetic properties but have been explored primarily in single-layer geometries, limiting their performance and multifunctional capacity. Here we use advanced two-photon lithography to realize multilayer scattering structures that achieve highly nontrivial optical transformations intended to process light just before it reaches a focal plane array. Computationally optimized multispectral and polarimetric sorting devices are fabricated with submicron feature sizes and experimentally validated in the mid-infrared. A final structure shown in simulation redirects light based on its angular momentum. These devices demonstrate that with precise 3-dimensional nanopatterning, one can directly modify the scattering properties of a sensor array to create advanced imaging systems.
© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. We thank the staff at Northrop Grumman for allowing us to carry out mid-infrared measurements at their facility with their equipment and to Orrin Kigner for assistance with coordination as well as measurement advice. Further, we acknowledge Chase Ellis from the U.S. Naval Research Laboratory and Professor Joe Tischler from University of Oklahoma for initial measurement and fabrication assistance as well as continued advice on the experimental setup and fabrication parameters. We thank Malina Strugaru for work on characterizing and verifying aspects of Nanoscribe fabrication, and Dr. Amir Arbabi, Dr. Oscar Bruno, Dr. Hyounghan Kwon and Ian Foo for helpful conversations and advice. The computations presented here were conducted in the Resnick High Performance Center, a facility supported by Resnick Sustainability Institute at the California Institute of Technology. This work was funded by Defense Advanced Research Projects Agency (HR00111720035), Rothenberg Innovation Initiative (RI2), Clinard Innovation Fund at Caltech and Army Research Office (W911NF-22-1-0097). Contributions. G.R., S.C.M., and A.F. conceived the project. G.R. carried out optimization, fabrication, and measurement of devices in the manuscript with input from other authors. C.B. consulted and provided critical feedback on optimization and measurement techniques and data analysis. T.Z. consulted on fabrication and optimization methods. J.C.G. and P.W.C.H. provided help with design and construction of the experimental setup as well as invaluable consultation on measurement results, as well as hosted G.R. for measurements on many occasions at Northrop Grumman. G.R. prepared the manuscript with input from all authors. Data availability. Data to support the conclusions in the manuscript can be provided on request. Competing interests. The authors have filed the following patents related to this work: Color and multi-spectral image sensor based on 3d engineered material (US20200124866A1) Broadband Polarization Splitting Based on Volumetric Meta-Optics (US20220004016) CMOS color image sensors with metamaterial color splitting (US11239276B2) There are no other competing interests.
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