3rd order nonlinear optical properties of Au: SiO2 nanocomposite films with varying Au particle size

Four Au:SiO2 composite films with varying Au particle size at fixed volume fraction were fabricated by alternate sputtering, and their 3rd order nonlinear optical properties were investigated by the z-scan technique using picosecond pulse laser. TEM analysis was used to estimate the particle size for samples with varying Au nominal thickness, and size dependent linear absorption spectra were examined. Particle size dependence on the imaginary part of 3rd order susceptibility at surface plasmon wavelength together with the dispersion of the real and the imaginary components around surface plasmon wavelength were resolved and compared with the theoretical values.