Nonlinear interfaces: intrinsically nonparaxial regimes and effects

Abstract. The behaviour of optical solitons at planar nonlinear boundaries is a problem rich in intrinsically nonparaxial regimes that cannot be fully addressed by theories based on the nonlinear Schrodinger equation. For instance, large propagation angles are typically involved in external refraction at interfaces. Using a recently proposed generalised Snell's law for Helmholtz solitons, we analyse two such eects: nonlinear external refraction and total internal re\nection at interfaces where internal and external refraction, respectively, would be found in the absence of nonlinearity. The solutions obtained from the full numerical integration of the nonlinear Helmholtz equation show excellent agreement with the theoretical predictions. PACS numbers: 42.65.Tg, 42.81.Dp Nonlinear interfaces: intrinsically nonparaxial regimes and eects 2