Spatial solitons and light-induced instabilities in colloidal media.

We study nonlinear light propagation in colloidal nanosuspensions. We introduce a novel model for the nonlinear response of colloids which describes consistently the system in the regimes of low and high light intensities and low/large concentrations of colloidal particles. We employ this model to study the light-induced instabilities and demonstrate the formation of stable spatial solitons as well as the existence of a bistability regime.