▎ 摘　　要

In this paper, a structure based on metal-graphene-insulator-metal (MGIM) is designed as a tunable plasmonic perfect absorber (PPA) in the FIR-band range. Simulation results performed with the 3D finite difference time domain (FDTD) method show that in the perpendicular incidence of a plane wave light in the range of 35 to 105 mu m, the absorption spectrum of the proposed device has a resonance peak with absorption above 95%, which can show excellent tunability by applying a gate bias voltage to the graphene nanolayers in the structure. In our proposed structure unit cell, there is a C-1 graphene nanolayer in the center and a C-2 graphene nanolayer around it that bias voltage is applied only to C-2, then changing the chemical potential of the two graphene nanolayers relative to each other, the absorption spectrum of the device shifts in the desired wavelength range.