Designing Graphene-Based Absorber by Using HIE-FDTD Method

A hybrid implicit explicit-finite-difference time-domain (HIE-FDTD) method is used to simulate a graphene-based absorber. Both the interband conductivity and intraband conductivity of the graphene are incorporated into the HIE-FDTD method directly through an auxiliary difference equation. Because the time step size in the proposed method is not confined by the fine spatial cells in the graphene layer, the simulation time of the proposed method is greatly reduced compared with that of the conventional FDTD method. By using the proposed HIE-FDTD method, a graphene-based absorber is simulated and analyzed. The numerical result shows that the operating frequency of the absorber is tunable through controlling graphene's chemical potential. It also shows that the interband conductivity has an important effect on the performance of the graphene device, especially at the frequency band larger than 10 THz.