超宽谱透射式的太赫兹波正交偏振转换器  

Ultra-broadband cross-polarization converter for terahertz waves in the transmission

作　　者：李恒一 张权 赵伟[1] 郑虹[1] 朱玲[1] LI Heng-yi, ZHANG Quan, ZHAO Wei, ZHENG Hong, ZHU Ling(School of Physical Sciences, University of Science and Technology of China, Hefei 230026, Chin)

机构地区：[1]中国科学技术大学物理学院,安徽合肥230026

出　　处：《物理实验》2018年第8期1-5,共5页Physics Experimentation

基　　金：仿真技术在大学物理实验中的应用及实践(No.2016jyxm1157)

摘　　要：利用CST电磁场仿真软件模拟设计了基于开口谐振环-介质-光栅3层结构的超宽谱透射式的太赫兹波正交偏振转换器件,研究了各层透射系数谱以及结构参量对偏振转换的影响,通过计算结构电场和电流分布分析了器件的工作原理.模拟结果表明:设计的器件实现在0.5~2.7THz频谱内,将入射的y偏振太赫兹光转换成x偏振光,转换效率高达99%.由结构电场分布以及表面电流分布推出,入射的y偏振太赫兹光耦合到开口环上,形成振荡的电偶极子,并辐射出太赫兹波x偏振分量.底部光栅层的作用是透过x偏振分量,并将剩余的y偏振光反射回开口环层,并在开口环层和光栅层间形成法布里-珀罗反射进一步提高偏振转换效率.可通过优化介质层厚度、光栅宽度和阵列周期关键参量来优化器件的转换性能.A type of ultra-broadband cross-polarization converter based on split-ring resonators（SRR）-dielectric-grating structure in the terahertz range was proposed and simulated by the CST software.Effects of each layer,and parameters of structure on the transmission coefficient were studied,and the calculated electric field distribution and surface electric current distribution were also employed to analyzing the working principles.The simulation showed that the polarization-conversion ratio could be up to 99% within the range 0.5 THz to 2.7 THz in the process of the incident y-polarization was transformed to be x-polarization.It could be concluded from the simulated electric field distribution and surface electric current distribution,that the incident y-polarized wave coupled into the SRR and an oscillated dipole resonator could be formed and then x-polarized terahertz wave component was radiated.The function of the grating was to allow only x-polarized waves to pass through but to reflect y-polarized ones.The F-P resonance was introduced into the structure within the split-ring resonators and the grating,the reflection enhanced the conversion further.The performances of the device could be optimized by scanning the dielectric thickness,grating width and the array period.

关 键 词：太赫兹波 偏振器 超构材料 CST 

分 类 号：O43[机械工程—光学工程]