Tunable THz optical bistability in graphene-based heterostructures

We investigate theoretically the THz optical bistability properties of graphene-based heterostructures. We derive a simple procedure to calculate the nonlinear transmission in graphene-based heterostructures. It is found that the hysteretic response occurs when the frequency of the incident light is less than critical frequency. Compared with the traditional nonlinear materials, THz optical bistability can be tuned more effectively in the proposed structure. It is shown that the optical bistability can be electrically controlled via suitably varying the applied voltage on the graphene, and can also be tuned by adjusting incident angle, the frequency of the incident light, and the refractive index of the constituent materials. The bistable thresholds can be lowered markedly by decreasing the Fermi energy or incident angle.