Cheng Yongzhi, Chen Fu, Luo Hui
School of Information Science and Engineering, Wuhan University of Science and Technology, Wuhan, 430081, People's Republic of China.
School of Optical and Electronic Information, Huazhong University of Science and Technology, 430074, Wuhan, People's Republic of China.
Nanoscale Res Lett. 2021 Jan 14;16(1):12. doi: 10.1186/s11671-021-03474-6.
In this paper, we present a plasmonic chiral metasurface absorber (CMSA), which can achieve high selective absorption for right-handed and left-handed circular polarization (RCP, "+", and LCP, "-") lights at optical frequency. The CMSA is composed of a dielectric substrate sandwiched with bi-layer fourfold twisted semicircle metal nanostructure. The proposed CMSA has a strong selective absorption band, where absorption peaks for LCP and RCP lights occur at different resonance frequencies, reflecting the existence of a significant circular dichroism (CD) effect. It is shown that the absorbance of the CMSA can reach to 93.2% for LCP light and 91.6% for RCP light, and the maximum CD magnitude is up to 0.85 and 0.91 around 288.5 THz and 404 THz, respectively. The mechanism of the strong chiroptical response of the CMSA is illustrated by electric fields distributions of the unit-cell nanostructure. Furthermore, the influence of the geometry of the proposed CMSA on the circular polarization selective absorption characterization is studied systematically.
在本文中，我们展示了一种等离子体手性超表面吸收器（CMSA），它能够在光频下对右旋和左旋圆偏振（RCP，“+”，以及LCP，“-”）光实现高选择性吸收。该CMSA由夹在双层四重扭曲半圆金属纳米结构之间的介电基板组成。所提出的CMSA具有一个强选择性吸收带，其中LCP光和RCP光的吸收峰出现在不同的共振频率处，这反映出显著的圆二色性（CD）效应的存在。结果表明，该CMSA对LCP光的吸光度可达93.2%，对RCP光的吸光度可达91.6%，并且在288.5太赫兹和404太赫兹附近，最大CD值分别高达0.85和0.91。通过晶胞纳米结构的电场分布说明了CMSA强手性光学响应的机理。此外，还系统研究了所提出的CMSA的几何结构对圆偏振选择性吸收特性的影响。
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