Dual-function terahertz metasurface based on vanadium dioxide and graphene

Abstract

A dual-function terahertz metasurface based on VO2 and graphene is proposed in this paper. It consists of a gold layer embedded with VO2 patches, a SiO2 spacer layer, a VO2 layer, graphene and a SiO2 spacer substrate. When the bottom VO2 layer is in the metallic state, the designed metasurface can achieve absorption. When the top VO2 patches are in the metallic state, the proposed metasurface can be used as a single-band absorber with terahertz absorptance of 99.7% at 0.736 THz. When the top VO2 patches are in the insulating state, the designed structure behaves as a dual-band absorber with an absorptance of 98.9% at 0.894 THz and 99.9% at 1.408 THz. In addition, the absorber is polarization insensitive and keeps good performance at large angles of incidence. When the bottom VO2 is in an insulating state, the metasurface shows electromagnetically induced transparency. The transparent window can be dynamically regulated by controlling the chemical potential of graphene. The proposed metasurface exhibits the advantages of terahertz absorption, electromagnetically induced transparency and dynamic control, which provides more options for the design of terahertz devices in the future.