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Proceedings Paper

Visible-frequency metasurfaces for broadband anomalous reflection and high-efficiency spectrum splitting (Presentation Recording)
Author(s): Zhongyang Li; Edgar Palacios; Serkan Bütün; Koray Aydin
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Paper Abstract

Metasurfaces offer new degrees of freedom in moulding the optical wavefronts by introducing abrupt and drastic changes in the amplitude, phase and/or polarization of electromagnetic radiation at the wavelength scale. By carefully arranging multiple subwavelength anisotropic or gradient optical resonators, metasurfaces have been shown to enable anomalous transmission, anomalous reflection, optical holograms and spin-orbit interaction. However, experimental realization of high-performance metasurfaces that can operate at visible frequency range has been a significant challenge due to high optical losses of plasmonic materials and difficulties in fabricating several subwavelength plasmonic resonators with high uniformity. Here, we propose a highly-efficient yet a simple metasurface design comprising of a single, anisotropic trapezoid-shape antenna in its unit cell. We demonstrate broadband (450 - 850 nm) anomalous reflection and spectrum splitting at visible and near-IR frequencies with 85% conversion efficiency. Average power ratio of anomalous reflection to the strongest diffraction mode was calculated to be on the order of 1000 and measured to be on the order of 10. The anomalous reflected photons have been visualized using a CCD camera, and broadband spectrum splitting performance has been confirmed experimentally using a free space, angle-resolved reflection measurement setup. Metasurface design proposed in this study is a clear departure from conventional metasurfaces utilizing multiple, anisotropic and/or gradient optical resonators, and could enable high-efficiency, broadband metasurfaces for achieving flat high SNR optical spectrometers, polarization beam splitters, directional emitters and spectrum splitting surfaces for photovoltaics.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9544, Metamaterials, Metadevices, and Metasystems 2015, 954428 (5 October 2015); doi: 10.1117/12.2187115
Show Author Affiliations
Zhongyang Li, Northwestern Univ. (United States)
Edgar Palacios, Northwestern Univ. (United States)
Serkan Bütün, Northwestern Univ. (United States)
Koray Aydin, Northwestern Univ. (United States)

Published in SPIE Proceedings Vol. 9544:
Metamaterials, Metadevices, and Metasystems 2015
Nader Engheta; Mikhail A. Noginov; Nikolay I. Zheludev, Editor(s)

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