Switchable polarization-independent THz reflector/absorber

Abstract

This paper introduces a novel metamaterial switchable terahertz (THz) reflector/absorber, which incorporates a composite graphene and vanadium dioxide (VO2) structure. The structure comprises gold and graphene layers separated by VO2 dielectric layers. By leveraging the electrical adjustability of graphene and the temperature adjustability of VO2, the operating frequency and absorption amplitude of the absorption spectrum can be controlled by adjusting the Fermi levels of graphene and the conductivity of VO2. The designed dual-function switch can be utilized as a reflector when VO2 exhibits a metallic state and as a perfect multiband absorber when VO2 exhibits dielectric properties. Numerical simulation results demonstrate that the proposed device exhibits exceptional performance for TE and TM waves, achieving a more than 99% absorption rate at 2.2, 6.5, and 10.5 THz. This structure holds considerable potential for a wide range of applications, including temperature monitoring, stealth technology, wireless communication, and biomedicine.