Linear and nonlinear optical properties of gold nanocrystal-incorporated mesoporous silica thin films

Abstract

Two kinds of mesoporous silica thin films (MSTFs), embedded with gold nanocrystals (GNCs), are synthesized using different surfactants. The MSTFs are composed of well-ordered mesostructures and the GNCs are well crystallized in the pores of the thin films. Optical absorption peaks, due to the surface plasmon resonance of the GNCs, are observed. Both classical and semi-classical methods are used to describe the dielectric function of the GNCs in the analysis, which showed that the particle size, particle shape, particle filling ratio and the matrix structure determine the absorption properties of the GNC/MSTF nanocomposite. Third-order optical nonlinearity of the nanocomposite was studied by the z-scan technique. The GNC/MSTF nanocomposites exhibited large optical nonlinearities.