▎ 摘　　要

In this paper, the terahertz (THz) radiation based on the graphene is studied by theoretical analysis and particle-in-cell (PIC) simulation. We present the transition radiation (TR) of the charged particle traversing a monoatomic graphene layer under arbitrary incidence. By theoretical analysis, we find strongly tunable effects of the radiation field distribution related to the electron's incident angle, substrate permittivity and graphene conductivity. In the case of the normal incidence, the transition radiation exhibits strong symmetry and considerably more intensive than that at oblique incidence. Furthermore, the plasmon and radiation are simulated by a PIC code with the method of equivalent permittivity to deal graphene. With the PIC code, we observe the spatial-temporal dynamics of plasmon and transition radiation from graphene. Meanwhile, the PIC simulation results of radiation are in good agreement with those by theoretical analysis.