提出了一种基于单层超表面的双频太赫兹波线偏振变圆偏振转换器。该偏振转换器采用两个不同尺寸的十字型金属缝阵列结构形成两个线偏振变圆偏振转换频点, 从而实现双频的太赫兹波线偏振变圆偏振转换。计算结果表明, 设计的偏振转换器能在0.760 THz和1.068 THz将一束线偏振太赫兹波转换为圆偏振太赫兹波。该双频的线偏振变圆偏振转换器仅由单层的超表面组成, 结构简单易于制备, 因而为操控电磁波和设计新颖的太赫兹波器件提供了参照。

In this paper, we propose a dual-band terahertz linear-to-circular(LTC) polarization converter based on single-layer metasurface consisting of two different-sized metallic cross apertures.Each of them can be considered as a separated single-band LTC polarization converter on the corresponding resonance frequency, leading to a dual-band characteristic.Simulation result shows that the polarization converter can convert linearly-polarized terahertz wave into the left-handed circularly-polarized terahertz wave at 0.760 THz and 1.068 THz, respectively.In addition, this kind of dual-band LTC polarization converter is composed of single-layer metasurface which is beneficial to device fabrication.Such polarization converter will provide a reference for manipulating electromagnetic wave and designing novel terahertz devices.