Design of tunable dual-band terahertz perfect absorber base on graphene

Abstract

In this paper, a novel tunable dual-band graphene-based perfect absorber which features a three-layer structure consisting of a monolayer graphene sheet and a metallic mirror separated by a thin Si layer with circular microcavity array is designed and systematically investigated. The simulation results show that the two perfect absorption peaks (99.7% and 99.5%) are achieved at 4.13 and 4.38 THz. The two resonance modes are caused by different electric and magnetic field distributions, resulting in different tuning properties. The absorption peaks could be tuned by adjusting the chemical potential of the monolayer graphene. In addition, the influences of the structural parameters such as period, thickness of the Si layer, depth and radius of the circular microcavity on the absorption characteristics of the absorber have been studied and presented.