一种同极化和交叉极化复用的双通道圆极化太赫兹超表面

A dual-channel circularly polarized THz metasurface with co-polarization and cross-polarization multiplexing

摘要:

本文提出了一种同极化和交叉极化复用的双通道圆极化太赫兹超表面，结合几何相位和传输相位原理，能实现对反射共极化和交叉极化圆极化波独立的相位控制。提出的超表面单元结构由双层“十字”形金属贴片和金属底板组成，改变“十字”的臂长，可以实现对x、y线极化波全相位控制。通过对同极化和交叉极化的解耦条件分析，改变“十字”结构的臂长和旋转角度，最终实现了对反射共极化和交叉极化的相位独立控制。基于提出的单元，设计了太赫兹轨道角动量产生器，在0.8 THz右旋圆极化波入射下，分别产生了携带+1阶轨道角动量的左旋圆极化波和携带+2阶轨道角动量的右旋圆极化波，所提出超表在通信、雷达、成像等领域具有潜在的价值。

Abstract:

This paper proposes a dual-channel circularly polarized terahertz metasurface that multiplexes co-polarization and cross-polarization. By integrating the geometric phase principle and transmission phase principle, independent phase control over reflected co-polarized and cross-polarized circularly polarized waves is achieved. The proposed metasurface unit consists of a double-layer "cross" shaped metal patch and a bottom metal plate. By adjusting the arm length of the "cross," full-phase control of x and y linearly polarized waves can be achieved. Through the analysis of decoupling conditions for co-polarization and cross-polarization, by changing the arm length and rotation angle of the "cross" structure, independent phase control over reflected co-polarized and cross-polarized wave is realized. Based on the proposed unit, a terahertz orbital angular momentum generator was designed. Under the incidence of 0.8 THz right-handed circularly polarized wave, left-handed circularly polarized waves with carrying +1 order orbital angular momentum and right-handed circularly polarized waves with carrying +2 order orbital angular momentum are generated. The proposed metasurface has potential value in the field of communication, radar, and imaging.