Nanocomposite thin films of Ga5Sb10Ge25Se60 chalcogenide glass for optical limiting applications

We report a low-cost, scalable method to fabricate optical grade composite thin films for nonlinear optical applications. The transmission and reflection spectra of prepared Ga5Sb10Ge25Se60/PVA composite films were investigated. Optical band gap of the thin films were calculated using Tauc’s extrapolation method. The band gap of the nanocomposite thin films were found to be tunable depending on the grain size of the films. Nonlinear optical characterization of samples were studied by the Z-scan technique using an Nd:YAG laser (532 nm, 7 ns, 10 Hz). Sequential Z-scan traces were made in four regimes of intensity for films with three different grain sizes. The Z-scan spectra reveal a strong nonlinear absorption depending on the grain size of the films suggesting that the new materials are promising candidates for the development of nonlinear optical devices and are extremely perspective as optical limiters of intense short pulse radiation.

Research highlights
► We report a low-cost, scalable method to fabricate optical grade composite thin films of Ga5Sb10Ge25Se60/PVA composite films for nonlinear optical applications.
► Optical band gap of the nanocomposite thin films were found to be tunable depending on the grain size of the films.
► Nonlinear optical characterisation of samples studied by the Z-scan technique reveal a strong reverse saturable absorption through two photon absorption.
► NLO response of these samples suggesting that the new materials are promising candidates for the development of nonlinear optical devices.
► Ga5Sb10Ge25Se60/PVA composite films are extremely perspective as optical limiters of intense short pulse radiation.