Tunable multiband metamaterial perfect absorber based on a metal-graphene multilayer structure.

In this paper, a tunable multiband metamaterial perfect absorber based on a metal-graphene multilayer structure is proposed, and the absorber consists of a metal layer, graphene, and a dielectric layer. We demonstrate that the absorber has 99.51% and 99.96% absorption at 2.78 THz and 6.78 THz, respectively. The surface plasmonic excitonic resonance of graphene at terahertz frequencies, as well as electromagnetic resonance, is used to produce multiple absorption peaks. We studied the physical mechanism of a perfect absorber using the impedance matching idea and electric field distribution. The absorbance of the absorption spectrum can be tuned by adjusting the Fermi energy level, relaxation time, medium thickness, or breadth of the cut graphene rectangle. Due to the geometrical symmetry of the structure, the proposed absorber is polarization-insensitive and has unique optical performance over a wide range of incidence angles. The proposed structure is simple to implement and is appropriate for sensing, imaging, and filtering. [ABSTRACT FROM AUTHOR]