Multilayer graphene based optical bistability

Abstract

In this paper, optical bistability of multilayer graphene structures is proposed and investigated. Here, results show that in spite of reduction of the Fermi level, we have optical bistability behavior in multilayer graphene structures in comparison to a single layer one. Also, the hysteresis width and threshold values are adjustable. It should be mentioned that the layer numbers can be increased to specific numbers because of large loss and low on-state transmission due to electron–phonon relaxation time. Combination of the Fermi level and layer numbers provides us appropriate tuning to achieve desirable hysteresis width, threshold values, and on-state to off-state transmission ratio. Considering typical electron–phonon relaxation time of 1 ps, silicon as the dielectric medium, and the Fermi level about 0.7 eV, a structure with four graphene layers gives us on-state to off-state transmission ratio of about 11.48, on-state transmission of 0.31, and hysteresis width of 1.24 MV/m, which seems to be favorable at 1 THz and normal incidence condition. Our results support using multilayer graphene structures for future optical bistability-based low-power and tunable optical devices.