Spatial phase modulation due to quintic and septic nonlinearities in metal colloids.

We report spatial self- and cross-phase modulation effects in metal-dielectric nanocomposites (MDNCs) whose nonlinear (NL) response is dominated by the quintic or septic refractive nonlinearity. The MDNCs consist of silver nanoparticles (NPs) suspended either in acetone or carbon disulfide and their effective NL susceptibilities are controlled by adjusting the volume fraction occupied by the NPs and the incident laser intensity. A theoretical treatment based on the Maxwell-Garnett model was developed to include contributions up to the seventh-order susceptibility showing a very good agreement with the experimental results.