Investigation of nonlinear refraction and nonlinear absorption of semiconductor nanoparticle solutions prepared by laser ablation

Abstract

We investigated As2S3 and CdS nanoparticle aqueous solutions prepared by laser ablation. Nonlinear optical characteristics of these solutions were studied by the Z-scan technique using Nd:YAG laser second harmonic radiation (λ = 532 nm, t = 55 ps). Nonlinear refractive indices, nonlinear absorption coefficients and third-order nonlinear susceptibilities of these solutions were measured. The comparison of nonlinear optical characteristics of As2S3 and CdS thin films and nanoparticle solutions was performed. It was shown that nonlinear refractive indices of As2S3 and CdS nanoparticles decreased with a growth in laser intensity. High nonlinear optical susceptibilities of such structures were attributed to size-related effects.