Synthesis and nonlinear optical properties of Zn doped TiO2 nano-colloids

This article summarizes investigations on nonlinear optical properties of Zn doped TiO2 nano-colloidal suspension under pulsed excitation. Zn (1, 2 and 5 wt%) doped TiO2 nanoparticles (NPs) have been synthesized using sol-gel method. Ultraviolet-visible studies revealed maximum blue shifting of absorption wavelength due to quantum size effect for undoped TiO2 NPs. Zn doped TiO2 NPs show slight increase in the absorption wavelength attesting the increase in the particle size with Zn doping. X-ray diffraction pattern confirms the presence of anatase phase of crystalline TiO2 with average crystallite size of 6 nm. FESEM and TEM micrographs attest formation of uniform spherical like TiO2 NPs. Nonlinear optical properties of these nano-colloids have been studied using open and closed aperture Z-scan technique employing the fundamental at 1064 nm of a 7ns mode-locked Nd-YAG laser operating at 10 Hz. 5 wt% Zn doped TiO2 nano-colloids show enhanced nonliear refractive and absorption coefficients.