▎ 摘　　要

Two-dimensional (2D) heterostructure materials have attracted increasing attention in ultrafast nonlinear optical applications due to their intriguing properties. Here, we fabricate a graphene/alpha-In2Se3 heterostructure by dropping alpha-In2Se3 dispersion onto the surface of few-layered graphene film and investigate its nonlinear optical responses. We show that the graphene/alpha-In2Se3 heterostructure has combined advantages of ultrafast relaxation (tau(1) similar to 78 fs, tau(2) similar to 14 ps) and a large effective nonlinear absorption coefficient (beta(eff) similar to -1.2 x 10(4) cm/GW) with relatively large modulation depth. We have further integrated the heterostructure into an erbium-doped fiber laser for mode-locked pulse generation. These results indicate that graphene/alpha-In2Se3 heterostructures are a promising 2D material for ultrafast nonlinear optical applications. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement