Total internal reflection of spatial solitons at interface formed by a nonlinear saturable and a linear medium

We study numerically and experimentally the reflection of spatial solitons at the interface between a nonlinear saturable-type medium and a linear one. We emphasize on determining the physical conditions under which the reflected beam at the interface conserve its nondiffracting properties. Depending on the incidence angle, we find three critical regions for spatial soliton conservation after reflection. We numerically show that the nonlinear Goos-Hanchen shift can have a dramatic effect on the diffracting properties of the reflected beam. (C) 2001 Published by Elsevier Science B.V.