Ultrafast nonlinear optical response of Au:TiO2 composite nanoparticle films

By using femtosecond optical Kerr effect (OKE) and pump-probe methods, we investigated the ultrafast nonlinear optical response of TiO2 films doped with gold nanoparticles. These films fabricated in a sol-gel way were heat treated at different temperatures, and the red shift of peak of the surface plasmon resonance with increase of heat treatment temperature was observed. The results of the experiment indicated that the third-order nonlinear susceptibility, about 10−10 esu, depended on the heat treatment temperature.