▎ 摘　　要

The dynamic optical properties of graphene are theoretically investigated in both length gauge and velocity gauge in the presence of ultrafast optical radiation field. The two gauges present different results of dynamic photo-induced carriers and optical conductance due to distinct dependencies on electric field and non-resonant optical absorption, while the two gauges give identical results in the steady state time. It shows that the choice of gauge affects evidently the dynamic optical properties of graphene. The velocity gauge represents an outcome of a real physical experiment. (C) 2014 AIP Publishing LLC.