Dynamically tunable and transmissive linear to circular polarizer based on graphene metasurfaces

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 degrees 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 onCOMSOL Multiphysics. (C) 2019 Optical Society of America