Switchable Polarization Selective Terahertz Wavefront Manipulation in a Graphene Metasurface

We propose a graphene-based metasurface to investigate the function of switchable polarization selective wave manipulation in THz regime by using the finite-difference time-domain method. The proposed metasurface consists of two layers of graphene arrays, polymer dielectric spacer and a gold mirror film, which can be switched between two states by simply biasing the two graphene layers on and off with the designed voltage and zero voltage without reconfiguring the Fermi energy distribution. One state is for x polarized wave manipulation and the other is for y polarization incidence. Then, the functions of switchable polarization selective anomalous reflection and focusing effect for 6 THz wave are realized by configuring the structure with specific values of Fermi energy. Moreover, we also designed the structure to focus at other spatial positions and another working frequency of 5.5 THz by reconfiguring the Fermi energy distributions.