Nonlinear absorption, nonlinear scattering, and optical limiting properties of MoS2–ZnO composite-based organic glasses

Abstract

MoS₂–ZnO composites were synthesized using a solution-based method. The scanning electron microscopy and transmission electron microscopy analysis demonstrated that ZnO nanoparticles with a size of about 4.5 nm were coated on the basal surface of MoS₂ nanosheets with an expanded spacing of the (002) plane. The MoS₂–ZnO composite-based poly(methyl methacrylate) (PMMA) organic glasses (MoS₂–ZnO–PMMA organic glasses) were prepared through a polymerization process. The nonlinear absorption (NLA), nonlinear scattering (NLS), and optical limiting (OL) properties of the MoS₂–ZnO–PMMA organic glasses with different amounts of MoS₂–ZnO were investigated using a modified Z-scan technique. Compared to MoS₂–PMMA and ZnO–PMMA organic glasses, the MoS₂–ZnO–PMMA organic glasses exhibited enhanced NLA, NLS, and OL properties, which were attributed to the interfacial charge transfer between MoS₂ nanosheets and ZnO nanoparticles, the layered structure of MoS₂ nanosheets, the small size effect of ZnO nanoparticles, and the local field effect. In addition, a changeover from saturable absorption (SA) to reverse saturable absorption (RSA) could be realized in the MoS₂–ZnO–PMMA organic glasses by adjusting the input energy. The total nonlinear extinction coefficient and response time of the MoS₂–ZnO–PMMA organic glasses could be up to 2380 cm GW⁻¹ and several hundred picoseconds, respectively. Compared to the MoS₂ films, the MoS₂–ZnO–PMMA organic glasses have higher optical damage threshold, better mechanical strength and flexibility. Thus the MoS₂–ZnO–PMMA organic glasses are very promising for optical devices such as optical limiters, optical shutters, ultrafast lasers, and ultrafast optical switches.