Switchable trifunctional terahertz absorber for both broadband and narrowband operations

Abstract

In this paper, we proposed a multilayer terahertz absorber composed of hybrid graphene and vanadium dioxide ( VO 2 ). Based on electrical controlling of graphene and thermal tuning of VO 2 , three different switchable absorption states are achieved in one structure. When VO 2 is in the metal phase and the Fermi level of graphene is set as 0 eV , high-frequency broadband (bandwidth, 5.45THz) absorption from 4.5 to 9.95THz is demonstrated. While VO 2 is switched to the insulator state, absorption states depend on the Fermi energy of graphene. As the Fermi level changes from 1 eV to 0 eV , the absorption can be switched from low-frequency broadband (bandwidth, 2.86THz) to dual-frequency absorption. The effect of geometric parameters and fabrication tolerance on the robustness of the absorption properties is explored. The proposed absorber has three switchable states through modulation of graphene and VO 2 , which is expected to realize potential applications in modulating, filtering, detecting, and other fields.