Nonlinear refractive index of the gold nanoparticle/silicon quantum dot hybrid structure

Abstract

The nonlinear refractive index n2 of hybrid structure composed of metal nanoparticle, Au, and a silicon quantum dot is measured and calculated by means of experimental and theoretical methods, respectively. Experimentally, gold nanoparticles are prepared by laser ablation in liquid method and Si quantum dot by liquid jet method. By using Z-scan technique, the mixture of them is exposed by 532 nm pump light, in close aperture configuration, to obtain the nonlinear refractive index. Moreover, hybrid structure is modeled, and the third-order nonlinear susceptibility is calculated by the local field theory. Our results show enhanced third-order nonlinear susceptibility and as a result nonlinear refractive index of the sample in the presence of the gold nanoparticles theoretically by the extracted nonlinearity experimentally.