可调控的太赫兹多频带吸收器特性

Characteristics of Tunable Terahertz Multi-Band Absorber

基于不同形状和大小的谐振环对电磁场具有不同的响应原理,设计了对4个频带具有电磁响应的、由圆形谐振环结构组成的太赫兹吸收器。采用时域有限差分法(FDTD)研究了该吸收器的特性,通过改变顶层金属环形图案几何尺寸、中间层电介质厚度以及顶层金属圆环处的硅电导变化率,对太赫兹多频带吸收器进行设计与仿真。在耦合后的多频吸收器的吸收峰中,低频部分被完美吸收,高频部分吸收率由70%增至94%。同时,随着电导率变化,低频分别从0.775 THz和1.064 THz移动到0.697 THz和1.017 THz,分别移动了78 GHz和47 GHz,实现了连续频率调谐。

A terahertz absorber comprising a circular resonant ring structure with four response frequency bands has been designed based on the principle of different responses of resonant rings exhibiting different sizes and shapes to electromagnetic fields. In this study, the absorber characteristics are studied using the finite-difference time-domain method. The terahertz absorber is designed and simulated by changing the geometrical size of the top metal ring pattern, the thickness of the dielectric layer in the middle layer, and the change rate of the silicon conductivity at the top metal ring. When the terahertz absorber is coupled with a multi-frequency absorber, the absorption at low frequencies reaches perfect absorption and the absorption rate at high frequencies increases from 70% to 94%;further, the low-frequency shifts from 0.775 THz and 1.064 THz to 0.697 THz and 1.017 THz, respectively, with a change in conductivity. The frequencies of 78 GHz and 47 GHz are shifted to achieve continuous frequency tuning.