Si Jiangnan, Liu Shuang, Yang Weiji, Yu Xuanyi, Zhang Jialin, Deng Xiaoxu
State Key Laboratory of Advanced Optical Communication Systems and Networks, Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
Nanomaterials (Basel). 2020 Sep 1;10(9):1733. doi: 10.3390/nano10091733.
A broadband near-perfect absorber is analyzed by an amorphous silicon (a-Si) hook shaped nanostructure metasurface. The transmission and reflection coefficients of the metasurface are investigated in the point electric and magnetic dipole approximation. By combining square and semicircle nanostructures, the effective polarizabilities of the a-Si metasurface calculated based on discrete dipole approximation (DDA) exhibit broadened peaks of electric dipole (ED) and magnetic dipole (MD) Mie resonances. The optical spectra of the metasurface are simulated with different periods, in which suppressed transmission are shifted spectrally to overlap with each other, leading to broadened enhanced absorption induced by interference of ED and MD Mie resonances. The angle insensitive absorption of the metasurface arrives 95% in simulation and 85% in experiment in spectral range from 564 nm to 584 nm, which provides potential applicability in nano-photonic fields of energy harvesting and energy collection.
一种宽带近完美吸收体由非晶硅（a-Si）钩形纳米结构超表面进行分析。在点电偶极和磁偶极近似下研究了该超表面的透射和反射系数。通过结合方形和半圆形纳米结构，基于离散偶极近似（DDA）计算的a-Si超表面的有效极化率呈现出电偶极（ED）和磁偶极（MD）米氏共振的展宽峰。对不同周期的超表面光谱进行了模拟，其中抑制的透射在光谱上发生偏移以相互重叠，导致由ED和MD米氏共振干涉引起的吸收增强展宽。在564nm至584nm的光谱范围内，该超表面的角度不敏感吸收在模拟中达到95%，在实验中达到85%，这在能量收集和能量采集的纳米光子领域提供了潜在的适用性。
