Graphene/α-In2Se3 heterostructure for ultrafast nonlinear optical applications

Abstract

Two-dimensional (2D) heterostructure materials have attracted increasing attention in ultrafast nonlinear optical applications due to their intriguing properties. Here, we fabricate a graphene/α-In2Se3 heterostructure by dropping α-In2Se3 dispersion onto the surface of few-layered graphene film and investigate its nonlinear optical responses. We show that the graphene/α-In2Se3 heterostructure has combined advantages of ultrafast relaxation (τ1 ∼ 78 fs, τ2 ∼ 14 ps) and a large effective nonlinear absorption coefficient (βeff ∼ −1.2 × 104 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/α-In2Se3 heterostructures are a promising 2D material for ultrafast nonlinear optical applications.