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

We investigated As 2 S 3 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 As 2 S 3 and CdS thin films and nanoparticle solutions was performed. It was shown that nonlinear refractive indices of As 2 S 3 and CdS nanoparticles decreased with a growth in laser intensity. High nonlinear optical susceptibilities of such structures were attributed to size-related effects.