Nonlinear interferometry and phase measurements for surface second-harmonic generation in a dispersive geometry

Abstract

Direct measurement of the phase of the surface nonlinear susceptibility is based on the interference of nonlinear optical signals. Up to now, this has not been possible for Second-Harmonic Generation (SHG) in geometries such as Total Internal Reflection (TIR) due to the refractive dispersion of harmonic and fundamental light created in TIR. We demonstrate two schemes which enable us to overcome this dispersion, leading to interference between two second-harmonic signals generated consecutively by the same laser. The advantages and limitations of the two approaches are discussed. We use this technique to check the theoretical predictions for the nonlinear Fresnel factors for SHG in the TIR geometry.