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 refle cted beam at the interface conserve its nondiffracting properties. Dependin g on the incidence angle, we find three critical regions for spatial solito n conservation after reflection. We numerically show that the nonlinear Goo s-Hanchen shift can have a dramatic effect on the diffracting properties of the reflected beam. (C) 2001 Published by Elsevier Science B.V.