A dynamically tunable and transmissive polarization converter, based on graphene metasurfaces, has been proposed in the terahertz range. In this paper, left-handed circular polarization (LHCP) with bandwidth from 5.15 to 5.52 THz is realized via the superimposition of two transmissive orthogonal components with a near-90° phase difference. By varying the Fermi energy, the working frequencies of the converter can be dynamically controlled, which also implies the linear to circular polarization conversion originates from the excitation of graphene surface plasmon. The absorption loss decreases with increasing electron scattering time. All simulation results have been conducted based on COMSOL Multiphysics.

中文翻译：

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基于石墨烯超表面的可动态调谐和透射的线性至圆偏振器

已经提出了在太赫兹范围内基于石墨烯超表面的动态可调谐和透射偏振转换器。在本文中，通过叠加两个相位差接近90°的透射正交分量，实现了带宽为5.15至5.52 THz的左旋圆极化（LHCP）。通过改变费米能量，可以动态控制转换器的工作频率，这也暗示了线性到圆极化的转换源自石墨烯表面等离子体激元的激发。吸收损耗随着电子散射时间的增加而减小。所有仿真结果均基于COMSOL Multiphysics进行。