High-Efficiency Broadband Anomalous Reflection by Gradient Meta-Surfaces

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• 作者：Shulin Sun ; Kuang-Yu Yang ; Chih-Ming Wang ; Ta-Ko Juan ; Wei Ting Chen ; Chun Yen Liao ; Qiong He ; Shiyi Xiao ; Wen-Ting Kung ; Guang-Yu Guo ; Lei Zhou ; Din Ping Tsai
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：December 12, 2012
• 年：2012
• 卷：12
• 期：12
• 页码：6223-6229
• 全文大小：448K
• 年卷期：v.12,no.12(December 12, 2012)
• ISSN：1530-6992

文摘

We combine theory and experiment to demonstrate that a carefully designed gradient meta-surface supports high-efficiency anomalous reflections for near-infrared light following the generalized Snell鈥檚 law, and the reflected wave becomes a bounded surface wave as the incident angle exceeds a critical value. Compared to previously fabricated gradient meta-surfaces in infrared regime, our samples work in a shorter wavelength regime with a broad bandwidth (750鈥?00 nm), exhibit a much higher conversion efficiency (80%) to the anomalous reflection mode at normal incidence, and keep light polarization unchanged after the anomalous reflection. Finite-difference-time-domain (FDTD) simulations are in excellent agreement with experiments. Our findings may lead to many interesting applications, such as antireflection coating, polarization and spectral beam splitters, high-efficiency light absorbers, and surface plasmon couplers.

Keywords:

Metamaterials; gradient meta-surfaces; generalized Snell鈥檚 law; high impedance surface; reflection phase; surface waves