Tri-control large angle electromagnetically induced reflection in metamaterials with graphene and vanadium dioxide

Abstract

Graphene and vanadium dioxide (VO2) have been widely studied because of their flexibly tunable conductivity. In this study, a multilayer structure of a graphene disk and a VO2 square ring is investigated. The proposed structure exhibits an electromagnetically induced reflection (EIR) that is caused by a bright mode coupled with a dark mode. Since the permittivity of graphene can be modulated by chemical potential and electron–phonon relaxation time, while that of VO2 can be modulated by temperature, the EIR effect of the proposed structure can be tuned by the chemical potential and relaxation time of graphene as well as the surrounding temperature. Therefore, a triple-tunable EIR effect is obtained. Simulation results confirm that the tunable EIR phenomenon is polarization-independent owing to the symmetry of the structure. Moreover, a large angle EIR effect is obtained up to an angle of 80°. Our results can contribute significantly in applications of terahertz devices, such as slow light devices, absorbers, switching devices, and sensors.