Exploiting a metal wire grating in total internal reflection geometry to achieve achromatic polarization conversion

作     者：XUDONG LIU XUEQUAN CHEN EDWARD P.J.PARROTT EMMA PICKWELL-MACPHERSON 

作者机构：Department of Electronic Engineering Chinese University of Hong Kong 

出 版 物：《Photonics Research》 (光子学研究（英文版）)

年 卷 期：2017年第5卷第4期

页      面：299-304页

核心收录：

学科分类：070207[理学-光学] 07[理学] 08[工学] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：Hong Kong Research Grants Committee(14201415 14205514) 

主　　题：THz 

摘      要：We demonstrate how a metal wire grating can work as a 45° polarization converter, a quarter-wave retarder, and a half-wave retarder over a broadband terahertz range when set up in total internal reflection geometry. Classical electromagnetic theory is applied to understand the mechanism, and equations to calculate the polarization state of reflected light are derived. We use a metal grating with a period of 20 μm and width of 10 μm on a fused silica surface: linearly polarized terahertz light incident from fused silica with a supercritical incident angle of 52° is totally reflected by the metal grating and air. The polarization of the terahertz light is rotated by 45°, 90°, and circularly polarized by simply rotating the wire grating. The performance is achromatic over the measured range of 0.1–0.7 THz and comparable to commercial visible light wave retarders.