▎ 摘　　要

Graphene-gamma MnS were prepared by facile one-step hydrothermal method. Structures and properties of samples were explored by characterization, and nonlinear optical (NLO) enhancement of nanocomposites (NCs) was fully studied. Nanoparticles and NCs were tested at 532 nm by a Z-scan technique. With gamma MnS attached in G layers, NLO susceptibility of graphene-gamma MnS was greatly improved under single-pulse laser irradiation compared with G and gamma MnS. The nonlinearity enhanced was attributed to local field effect and charge transfer between gamma MnS and graphene layers. And NLO property enhancement was restricted by non-radiative defects in graphene-gamma MnS. Exploring the mechanism of nonlinearity enhancement was significant for fabrication of NLO devices. However, the optical nonlinearity decreased first and then increased with further increased addition of GO, because the dispersion of gamma MnS attached on graphene surface might make density of sp(2) fragment and defects changed. Graphene-gamma MnS exhibited excellent and tunable NLO performance, illustrating that NCs materials have potential applications in NLO devices.