▎ 摘　　要

Graphene does not possess a band gap, and hot carrier relaxation in graphene is an ultrafast processs. This leads to a very low emission efficiency of graphene. We demonstrate bright multicolored frequency-upconverted photoluminescence from graphene via three-photon absorption by femtosecond laser injection at a communication wavelength 1.57 mu m. The broadband and multiwavelength emission from graphene is based on the model of ultrafast electron-hole pair recombination and asymmetrical energized electron-hole radiation recombination in graphene. Furthermore, we show photoluminescence variation with blue light emission in the graphene/silicon hybrid system, with 2-3 orders of emission efficiency increase. The results demonstrate hot carrier multiplication and hot carrier scattering in graphene and could help to study the population inversion and broadband lasing of graphene.