Improvement of terahertz beam modulation efficiency for baseless all-dielectric coded gratings  

作　　者：JIE JIANG BO FANG CHENXIA LI ZHI HONG XUFENG JING 

机构地区：[1]Institute of Optoelectronic Technology,China Jiliang University,Hangzhou 310018,China [2]Centre for THz Research,China Jiliang University,Hangzhou 310018,China [3]College of Metrology&Measurement Engineering,China Jiliang University,Hangzhou 310018,China

出　　处：《Photonics Research》2023年第10期1738-1750,共13页光子学研究（英文版）

基　　金：Natural Science Foundation of Zhejiang Province (LZ21A040003, LY22F050001);National Natural Science Foundation of China (62175224)。

摘　　要：Optical metasurfaces are two-dimensional ultrathin devices based on single-layer or multilayer arrays of subwave-length nanostructures. They can achieve precise control of phase, amplitude, and polarization on the subwave-length scale. In this paper, a substrate-free all-silicon coded grating is designed, which can realize the phase control of the outgoing beam after the y-polarized plane wave is vertically incident on the metasurface at 0.1 THz.Through a single-layer silicon nanoarray structure, a low-reflection anomalous transmission metasurface is realized, and a variety of different beam deflectors are designed based on these encoded gratings. We propose a coded grating addition principle, which adds and subtracts two traditional coded grating sequences to obtain a new coded grating sequence. The encoded supergrating can flexibly control the scattering angle, and the designed substrate-free all-silicon encoded grating can achieve a deflection angle of 48.59°. In order to verify the principle of coded grating addition, we experimented with cascade operation of two coded sequence gratings to obtain the flexible control of the terahertz beam of the composite supergrating. The principle of grating addition provides a new degree of freedom for the flexible regulation of the terahertz wavefront. At the same time, this method can be extended to the optical band or microwave band, opening up new ways for electromagnetic wave manipulation and beam scanning.

关 键 词：POLARIZATION BEAM DIELECTRIC 

分 类 号：O43[机械工程—光学工程]