Tunable ultra-narrowband and wide-angle graphene-based perfect absorber in the optical communication region

A tunable ultra-narrowband and wide-angle graphene-based perfect absorber, in which monolayer graphene is on top of the dielectric metasurface backed by a silver substrate, is proposed. Through finite-difference time-domain (FDTD) simulations, an ultra-narrowband perfect absorption peak with a 3 dB bandwidth of 0.5 nm, which is a remarkable value compared with the previous results, is realized in the optical communication region. Moreover, the absorption amplitude can be efficiently modulated by varying the Fermi energy of graphene. Furthermore, the proposed absorber can tolerate a wide range of incident angles and demonstrates a dependence on polarization.