基于圆形双箭头太赫兹线偏振转换器的设计及性能分析

Design and Performance Analysis of Terahertz Linear Polarization Converter Based on Circular Double-head Arrow

设计了一种基于圆形双箭头(circular double-head arrow,CDHA)单元结构阵列的高效太赫兹波线偏振转换器,该偏振转换器是由CDHA单元结构阵列上下两侧添加一对正交金属光栅构成。该结构在0.36~1.51THz下偏振转换率超过99%,相对带宽为123%,正交金属光栅与CDHA形成一个法布里-珀罗腔,可以有效地阻止交叉偏振反射和共偏振透射,显著增大了交叉偏振波的透射。不同线偏振波沿不同方向入射的透射特性仿真计算结果表明,该偏振转换器还可以用作太赫兹波分束器和不同线偏振态选择器,在低频段0.36~1.02 THz范围内,该器件依然可以保持较高的偏振转换率。

An efficient terahertz linear polarization converter based on circular double-head arrow(CDHA)element array is designed.The polarization converter is composed of a pair of orthogonal metal gratings added to the upper and lower sides of the CDHA element array.The structure has a polarization conversion rate of over 99%and a relative bandwidth of 123%at 0.36-1.51 THz.In this structure,the orthogonal metal grating and CDHA form a Fabry-Perot cavity,which can effectively prevent cross-polarized reflection and co-polarized transmission,and significantly increase the transmission of cross-polarized waves.The transmission spectra of different linearly polarized waves incident in different directions are simulated.It is found that the multilayer CDHA metasurface can also be used as a terahertz beam splitter and a selector of different linearly polarized states.It is shown that the device can still maintain a high polarization conversion rate in the low frequency range of 0.36-1.02 THz.