Experimental studies of a nonlinear interface

We describe the results of a detailed experimental study of the reflectivity of a nonlinear interface under the influence of intense ruby laser pulses incident in a Gaussian beam at grazing angles. The nonlinear interface was the interface between a linear optical material (glass) and a nonlinear material with a positive optical Kerr coefficient (CS
2
). Optical hysteresis was observed as a function of incident light intensity. The nonlinear reflectivity showed behavior which differs from the predictions of previously published plane-wave calculations. We interpret our results with the aid of a numerical analysis of a two-dimensional Gaussian beam case.