Plasmon logic gates and dual-narrowband absorption switching effect in hybrid structure composed of silver and spaced dual graphene monolayers

Abstract

We propose a hybrid structure composed of a silver mirror and two spaced graphene monolayers to enhance light absorption. A broad plasmon-induced reflection (PIR) window can be generated because of the destructive interference between the bright and dark modes, resulting in a dual-narrowband absorption switching effect. The dual-narrowband absorption switch is strongly dependent on the geometric structure parameters and dynamic tuning parameter of the hybrid structure, and each parameter has a wide tuning range for absorption state ‘on/on’. Especially, compared with the hybrid structure composed of a graphene monolayer and one-dimensional photonic crystal (1D PC), the proposed structure is simpler and easier to fabricate, and the dynamic tuning width of Fermi energy of graphene for light absorption state ‘on/on’ is significantly broadened (∼3 times). Compared with plasmon-induced transparency (PIT) systems, the absorption performance of graphene is greatly enhanced, and the absorption is increased from about 50% to higher than 97%. Moreover, by adjusting the widths of the graphene monolayers, NAND and NOR logic gates are realized, and the output contrast between logic states ‘1’ and ‘0’ is high up to 18.6 dB. This study may provide an approach to construct dual-narrowband absorption switches, perfect absorbers, and plasmon logic gates.