Optical Limiting Properties of Colloids Enhanced By Gold Nanoparticles Based on Thermal Nonlinear Refraction

In this work, thermo-opticalproperties of gold nanoparticle colloids arestudied using continuous wave (cw) laserirradiation at 532 nm. the nanoparticle colloidsare fabricated by 18 ns pulsed laser ablation ofpure gold plate in the distilled water. theformation of the nanoparticles has beenevidenced by optical absorption spectra andtransmission electron microscopy. thenonlinear optical properties of goldnanoparticles colloids are investigated by closedz-scan under irradiation of a low power cwlaser. it will be shown that the thermal lensmodel is in excellent agreement with theexperimental results of samples. the aperturelimittedoptical limiters based on the nonlinearrefraction of colloidal solution are presented.the tunability of limiting threshold of opticallimiters can be accomplished by engineering ofthe experimental geometry.