Self-focusing and spatial plasmon-polariton solitons.

We study nonlinear propagation of surface plasmon polaritons along an interface between metal and nonlinear Kerr dielectric. We demonstrate numerically self-focusing of a plasmon beam at large powers and the formation of slowly decaying spatial soliton in the presence of losses. We develop an analytical model for describing the evolution of spatial plasmon-solitons and observe a good agreement with numerical results.