Surface solitons due to second order cascaded nonlinearity

Abstract

In this paper we show theoretically that cascaded surface solitons can exist on the surface of a medium with the bulk inversion symmetry center. Although in the bulk of such media the second order nonlinearity vanishes, χ (2)=0, the optical quadratic nonlinearity appears due to the contribution of spatial derivatives of the fields to the nonlinear response. This nonlinearity is localized at the surface and leads to the cascaded χ (2) surface solitons.