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Off-axis metasurfaces for folded flat optics

The overall size of an optical system is limited by the volume of the components and the internal optical path length. To reach the limits of miniaturization, it is possible to reduce both component volume and path length by combining the concepts of metasurface flat optics and folded optics. In add...

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Autores principales: Born, Brandon, Lee, Sung-Hoon, Song, Jung-Hwan, Lee, Jeong Yub, Ko, Woong, Brongersma, Mark L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10497541/
https://www.ncbi.nlm.nih.gov/pubmed/37699876
http://dx.doi.org/10.1038/s41467-023-41123-x
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author Born, Brandon
Lee, Sung-Hoon
Song, Jung-Hwan
Lee, Jeong Yub
Ko, Woong
Brongersma, Mark L.
author_facet Born, Brandon
Lee, Sung-Hoon
Song, Jung-Hwan
Lee, Jeong Yub
Ko, Woong
Brongersma, Mark L.
author_sort Born, Brandon
collection PubMed
description The overall size of an optical system is limited by the volume of the components and the internal optical path length. To reach the limits of miniaturization, it is possible to reduce both component volume and path length by combining the concepts of metasurface flat optics and folded optics. In addition to their subwavelength component thickness, metasurfaces enable bending conventional folded geometries off axis beyond the law of reflection. However, designing metasurfaces for highly off-axis illumination with visible light in combination with a high numerical aperture is non-trivial. In this case, traditional designs with gradient metasurfaces exhibit low diffraction efficiencies and require the use of deep-subwavelength, high-index, and high-aspect-ratio semiconductor nanostructures that preclude inexpensive, large-area nanofabrication. Here, we describe a design approach that enables the use of low-index (n ≈ 1.5), low-aspect ratio structures for off-axis metagratings that can redirect and focus visible light (λ = 532 nm) with near-unity efficiency. We show that fabricated optical elements offer a very large angle-of-view (110°) and lend themselves to scalable fabrication by nano-imprint lithography.
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spelling pubmed-104975412023-09-14 Off-axis metasurfaces for folded flat optics Born, Brandon Lee, Sung-Hoon Song, Jung-Hwan Lee, Jeong Yub Ko, Woong Brongersma, Mark L. Nat Commun Article The overall size of an optical system is limited by the volume of the components and the internal optical path length. To reach the limits of miniaturization, it is possible to reduce both component volume and path length by combining the concepts of metasurface flat optics and folded optics. In addition to their subwavelength component thickness, metasurfaces enable bending conventional folded geometries off axis beyond the law of reflection. However, designing metasurfaces for highly off-axis illumination with visible light in combination with a high numerical aperture is non-trivial. In this case, traditional designs with gradient metasurfaces exhibit low diffraction efficiencies and require the use of deep-subwavelength, high-index, and high-aspect-ratio semiconductor nanostructures that preclude inexpensive, large-area nanofabrication. Here, we describe a design approach that enables the use of low-index (n ≈ 1.5), low-aspect ratio structures for off-axis metagratings that can redirect and focus visible light (λ = 532 nm) with near-unity efficiency. We show that fabricated optical elements offer a very large angle-of-view (110°) and lend themselves to scalable fabrication by nano-imprint lithography. Nature Publishing Group UK 2023-09-12 /pmc/articles/PMC10497541/ /pubmed/37699876 http://dx.doi.org/10.1038/s41467-023-41123-x Text en © The Author(s) 2023 https://creativecommons.org/licenses/by/4.0/Open Access 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 licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence 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 licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Born, Brandon
Lee, Sung-Hoon
Song, Jung-Hwan
Lee, Jeong Yub
Ko, Woong
Brongersma, Mark L.
Off-axis metasurfaces for folded flat optics
title Off-axis metasurfaces for folded flat optics
title_full Off-axis metasurfaces for folded flat optics
title_fullStr Off-axis metasurfaces for folded flat optics
title_full_unstemmed Off-axis metasurfaces for folded flat optics
title_short Off-axis metasurfaces for folded flat optics
title_sort off-axis metasurfaces for folded flat optics
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10497541/
https://www.ncbi.nlm.nih.gov/pubmed/37699876
http://dx.doi.org/10.1038/s41467-023-41123-x
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