▎ 摘　　要

A switchable polarization converter based on a graphene-vanadium dioxide (VO2) metamaterial is proposed, which is capable of switching between transmission mode and reflection mode. The proposed structure consists of a graphene resonator placed along the diagonal, a dielectric layer of SiO2, and a VO2 substrate with a metal grating. By changing the Fermi level of the graphene and the state of the VO2 , the simulation results show that the polarization converter can operate in the switching state, whether it is a transmission mode or a reflection mode. When the VO2 is in the insulating state, the transmitted polarization conversion ratio ( PCRt) can be tuned to below 2% (off-state) and above 99.5% (on-state) from 3.00 to 6.00 THz by controlling the graphene. When the VO2 operates in the metallic state, the reflected PCRr can achieve nearly 0 (off-state) and larger than 90.0% (on-state) from 3.76 THz to 4.15 THz by controlling the Fermi level of the graphene. In addition, the designed structure can maintain a stable performance during the reflected polarization conversion within the incidence angle of 60 degrees. Furthermore, we believe that this switchable polarization converter with a switching function has potential application prospects in high-density integrated and switching devices.