Nonlinear optical properties of ultra-fine nanocrystalline SnO synthesised through microwave-assisted hydrothermal route

摘要

The purpose of this Letter is to prepare and investigate the nonlinear optical properties of nanocryatalline SnO. Using a microwave-assistednhydrothermal method, nanoparticles of SnO have been synthesised. It was noticed that, at 600 W microwave power, the pure tetragonal singlenphase of SnO existed and at higher-power SnO2 starts appearing. The grain size of SnO was u00023 nm and UV–vis measurements showed thenexistence of an excitonic peak at u0002270 nm. The appearance of this excitonic peak for nanocrystallites SnO may be attributed to the conversionnof bandgap from indirect in bulk SnO to direct bandgap in nanocrystallites. The third-order nonlinear optical properties of SnO nanoparticlesnwere also studied using a continuous-wave He–Ne laser by z-scan technique. The nonlinear refractive indices of SnO nanoparticles werenobtained from close aperture in order of 1027ncm2n/W with negative sign and the nonlinear absorption indices of these nanoparticles werenobtained from open aperture with negative sign.