A Modified ‘Position Dispersion’ Method for Nonlinear Refraction Index Measurement

In this report, a modified ‘position dispersion’ method, in which the detecting aperture in the far-field is replaced by a circular board, is given to enhance the measurement sensitivity of nonlinear index, while keeps the simplicity. An increase of 5 times in sensitivity is obtained in our experiment, in which we employed a solution to produce the thermally induced nonlinearity.