Synthesis and nonlinear optical properties of silica capped I-VI Metal Sulfides

Abstract

A simple, facile route for preparing silica capped copper sulfide and silver sulfide nanoparticles at room temperature has been developed. Their crystalline, structural and optical properties were investigated and the optical limiting nature was studied from fluence-dependent transmittance measurements employing 5 ns laser pulses at 532 nm. Ag2S nanoparticles are found to have larger third order nonlinear optical coefficients with a lower limiting threshold of 1.7 Jcm-2. Large free carrier absorption is the dominating nonlinear absorption mechanism in ptype CuS and n-type Ag2S nanocrystals. The results pave the way to design good quality optical limiters for laser safety applications.