Measurement of the Dispersion of n2 in Wide-Gap Materials from the IR to UV

The recently published theory of Sheik-Bahae et al [1] predicts the dispersion of the nonlinear index of refraction in solids. In reference [1], the authors compared their theory with a large number of experimental data in which the dispersion of n2 was measured using the ratio of the incident photon energy and the energy gap of the solid, ħω/Eg. In most cases this ratio was chosen by using different materials which changes the energy gap and thus ħω/Eg. In this paper we directly determine the dispersion of n2 by measuring the nonlinear refractive index of the material at different laser wavelengths.