Single-step switching at a nonlinear interface

Theoretical predictions of the behavior of a light beam crossing a plane interface between a linear and nonlinear dielectric medium indicate staircased multiple threshold switching in nondiffusive media when an incident Gaussian beam instead of a plane wave is assumed. We report experimental findings showing unexpected high-contrast single-threshold switching, which may have important implications for optical signal processing. No evidence was found for the existence of bistable behavior indicated by previous experiments.