Dual-band enhanced optical absorptance of graphene with resonant tunneling in total internal reflection regime

We propose a stratified structure, where the monolayer graphene is sandwiched between two thin film stacks with optimized period number. A band-pass filter based on the stratified structure is realized. The dual-band enhanced optical absorptance of graphene with resonant tunneling in total internal reflection (TIR) regime is investigated theoretically. Both absorptance peaks are enhanced up to almost 100% in the pass-band filter based on resonant tunneling through a graphene sheet over the communication wavelength range due to the strong light field confinement. With the increasing of the bottom mirror layers, the values of the dual-band absorptance peaks improve accordingly while the peak locations are unchanged. The variation of the angle and wavelength can be exploited to realize tunable filters with good rejection.