Nonlinear optical properties of Au nanoparticles colloidal system: Local and nonlocal responses

Z-scan revealed thermal and electronic contributions for the nonlinear refractive index of highly stable colloid containing different concentrations of gold nanoparticles. Large enhancement factors were observed for values of n2 and dn∕dT of the colloid, due to the presence of the nanoparticles. Our results suggest that thermal effects will play an important role in the development of photonic applications involving nanostructured materials and in the investigation of nonlocal nonlinear phenomena.