Shearing interferometer based on second-harmonic generation and a novel technique of n(2) direct measurements

We present a new wave-front sensitive interferometry technique (called dispersion shearing interferometry) for the measurement of both the sign and the magnitude of n(2). The interference pattern is produced by two laterally shifted second harmonics of the laser source. Only the fundamental wave passes through the nonlinear sample, which is placed before the interferometer. We demonstrate this technique on an aggregated colloidal silver solution using a YAG:Nd laser and KTiOPO(4) frequency doublers.