Tunable terahertz reflective linear polarization convertor based on oval-shape-perforated graphene metasurface

In this paper, we present a simple design of a tunable reflective linear polarization convertor based on oval-shape-perforated-graphene (OSPG) metasurface (MS) in terahertz region. Simulation results indicated that the designed MS can achieve cross polarization conversion in a broadband frequency range of 0.93-1.21 THz with a polarization conversion ratio (PCR) of over 90%. At resonance frequency of 0.98 THz, the PCR is up to 99.8%. The simulated electric field distributions reveal that the perfect cross polarization conversion is mainly attributed to the excitation of the localized surface plasmon resonance (LSPR) mode. Furthermore, the both efficiency and bandwidth of the cross-polarization can be tuned easily by varying the external voltage to modify the chemical potential of the OSPG, which suggests numerous potential terahertz applications.