Observations on nonlinear optical properties of ZnS nanosheet, ZnS–ZnO composite nanosheet and porous ZnO nanostructures dispersed in aqueous medium

The nonlinear optical (NLO) absorption and refraction properties of different nanostructures, such as ZnS nanosheets, ZnS–ZnO composite and porous ZnO nanostructures, dispersed in de-ionized water, are reported by performing the z-scan technique with 532 nm ns pulsed laser radiation. The values of NLO coefficients of the materials are extracted from the experimental z-scan data. The two-photon induced free carrier absorption has been observed in the samples. The experimentally obtained two photon absorption coefficient of ZnS–ZnO nanocomposite is an order-of-magnitude larger that of ZnS nanoparticles. The presented results may open up new possibilities of using these materials in different NLO devices.