偏振可调的太赫兹光电导天线设计

Study on Polarization-controlled Terahertz Photoconductive Antenna

摘要:

提出了一种偏振可调的太赫兹光电导天线,其结构由四个弧形金属电极、低温砷化镓衬底和氮化硅抗反射涂层构成。通过对光电导天线的工作原理分析,可以发现弧形金属电极结构决定天线的辐射偏振,且衬底的载流子迁移率、载流子寿命和衬底材料对激光的吸收直接影响天线的辐射特性。利用COMSOL软件对该光电导天线进行建模仿真,其结果表明该光电导天线可以在45°方向倍增地辐射线偏振太赫兹波,且辐射强度相较于常规光电导天线提高了30%,辐射带宽高达10THz。所设计太赫兹光电导天线具有偏振可调、结构简单和易于加工等特点,在太赫兹光谱检测领域具有广阔的应用前景。

Abstract:

A terahertz photoconductive antenna with adjustable polarization is proposed, which consists of four arc structure metal electrodes, a low-temperature gallium arsenide substrate and an anti-reflection layer of silicon nitride. Through the analysis of the working principles of photoconductive antenna, it can be found that the arc metal electrode structure determines the radiation polarization of the antenna, and the carrier mobility, carrier life and laser absorption of the substrate material can directly affect the radiation characteristics of the antenna. The photoconductive antenna is modeled and simulated by COMSOL software, and the results show that the antenna can multiply the outgoing polarized terahertz wave in the 45° direction, and the radiation intensity is 30% higher than that of the conventional photoconductive antenna and the radiation bandwidth is up to 10THz. The designed terahertz photoconductive antenna has the characteristics of adjustable polarization, simple structure and easy processing, owning broad application prospects in the field of terahertz spectrum detection.