基于微纳结构太赫兹光电导天线辐射特性研究

Research on radiation characteristics of terahertz photoconductive antenna based on micro-nano structure

摘要:

光电导天线(PCA)作为常用的太赫兹发射器件，如何提高其辐射效率，成为国内外研究人员研究的重点。通过时域有限差分法对PCA辐射效率进行研究，在光敏层表面加入柱状结构，使更多的光被捕获到光敏层，模拟结果表明该结构具有显著增强辐射效率的作用。通过对比材料、柱状形状对增强效果的影响，结果表明，在同一种柱状结构下，银材料的PCA、金材料的PCA、砷化镓材料的PCA的增强效果依次降低；同一材料下，带有正六棱柱结构、圆柱形结构、正四棱柱结构的光PCA的增强效果依次降低。通过材料与结构的最佳组合，最高的增强效率为传统PCA的1 100%，最低的增强效率为传统PCA的150%。

Abstract:

Photo-Conductive Antenna(PCA) is a commonly used terahertz transmitting device. How to improve the radiation efficiency of PCA has become the research focus of domestic and foreign researchers. In this paper, the radiation efficiency of the PCA is studied by using the Finite Difference Time Domain(FDTD) method. The columnar structure is added to the surface of the photosensitive layer, so that more light is captured in the photosensitive layer. The simulation results show that the structure can significantly enhance the radiation efficiency. By comparing the enhancement effects of materials and columnar shapes, the results show that the enhancement effects of the PCA of silver material, gold material, and gallium arsenide material sequentially decrease in the same columnar structure; in the same material, the enhancement effects of the PCA with the regular hexagonal prism structure, the cylindrical structure, and the regular quadrangular prism structure decrease sequentially. Through the optimal combination of materials and structures, the highest and the lowest enhancement efficiencies are respectively 1 100% and 150% that of the traditional PCA.