NONLINEAR OPTICAL TRANSMISSIONOF SURFACE-MODIFIED NICKEL SULFIDENANOPARTICLES: SATURATION OF ABSORPTIONAND OPTICAL LIMITING

摘要

Saturable absorbers and optical limiters have contrary optical transmission properties. We reportobservations of simultaneous occurrence of both these effects in a nickel sulfide nanoparti-cle (average diameter 5 nm) solution and a simultaneous quantitative measurement of both.Intensity-dependent nonlinear transmission studies carried out using a 7 ns Nd:YAG laser at532 nm by the Z-scan method, revealed efficient optical limiting in nickel sulfide nanoparticlesuspensions. Induced nonlinear optical scattering was identified to be the mechanism of opticallimiting, and absorption at 532 nm was found to saturate. A modification of the conventionalZ-scan implementation led to the retrieval of the saturation intensity, which is otherwise over-shadowed by very strong nonlinear scattering.