Nonlinear optical response in Kronig-Penney type graphene superlattice in terahertz regime

摘要

The terahertz nonlinear optical response in Kronig-Penney (KP) type graphene superlattice is demonstrated. The single-, triple- and quintuple-frequencies of the fifth-order nonlinear responses are investigated for different frequencies and temperatures with the angle phi along the periodicity of the superlattice toward the external field tuning from 0 to pi/2. The results show that the fifth-order nonlinear optical conductance of graphene superlattice is enhanced in the terahertz regime when phi = 0, i.e. an external field is applied along the periodicity of the superlattice. The fifth-order nonlinear optical conductances at phi = 0 for different frequencies and temperatures are calculated. The results show that the nonlinear optical conductance is enhanced in low frequency and low temperature. Our results suggest that KP type graphene superlattices are preferred structures for developing graphene-based nonlinear photonics and optoelectronics devices.