Gold colloids in sol-gel derived SiO2 coatings on glass and their linear and nonlinear optical properties

Abstract

An organic-inorganic synthesis route to Au-colloid containing, transparent SiO2 coatings has been developed, using four different types of functionalized silanes as stabilizing ligands for the Au. By variation of the kind and the concentration of the stabilizing silane in the sol the onset temperature for the colloid formation varies between 100 and 300°C and the final colloid radii can be controlled in a range between 3 and 30 nm after densification of the composite coatings on glass at 500°C. The third order polarizability Xm(³) in the metal particles is one order of magnitude higher than in glass composites and exhibit a strong dependence on the ligand.