Polarization variable terahertz metasurface along the propagation path  

作　　者：Jitao Li Jingyu Liu Zhen Yue Jie Li Chenglong Zheng Fan Yang Hui Li Yating Zhang Yan Zhang Jianquan Yao 

机构地区：[1]Key Laboratory of Opto-Electronics Information Technology(Tianjin University),Ministry of Education,School of Precision Instruments and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China [2]Beijing Key Laboratory for Metamaterials and Devices,Key Laboratory of Terahertz Optoelectronics,Ministry of Education,and Beijing Advanced Innovation Center for Imaging Technology,Department of Physics,Capital Normal University,Beijing 100048,China

出　　处：《Fundamental Research》2025年第1期124-131,共8页自然科学基础研究(英文版)

基　　金：supported by National Key Research and Development Program of China(2021YFB2800703 and 2017YFA0700202).

摘　　要：Conventional metasurfaces for terahertz polarization are limited to performing lateral(in the x-y plane)polarization control of the output wave.In such cases,the polarization state remains unchanged in each output plane along the propagation path.Herein,we propose a terahertz polarization metasurface that operates longitudinally(i.e.,along the z-axis direction of propagation),which modifies the polarization state of each output plane throughout the propagation path.Our designed metasurface can control the phase delays of the left-handed and right-handed circularly polarized(LCP and RCP)components of the incident terahertz wave.This enables the LCP beam and RCP beam to converge to the z-axis through distinct paths,creating a Bessel beam.The proposed design achieved a linearly polarized terahertz wave including both LCP and RCP components with a precise phase differenceΔφat each point within a certain range along the z-axis.TheΔφvaries as the propagation distance,resulting in a rotated linearly polarized output wave along the propagation path,while the rotation angle ranges from 0 toπ.Based on the variable property of longitudinal polarization,we propose an application concept of dielectric refractive index sensing,in which an additional medium is placed in the terahertz propagation path and the unknown refractive index is determined by detecting the rotation angle of the output polarization state.Theoretically,the device might find potential applications in variable media excitation,terahertz communication,and terahertz radar ranging.

关 键 词：TERAHERTZ Metasurface Propagation path Polarization manipulation Longitudinal polarization Refractive index sensing 

分 类 号：O43[机械工程—光学工程]