Dispersion of the linear electro-optic coefficients and the non-linear susceptibility in GaP

The linear electro-optic effect in GaP has been investigated in the wavelength range 0.552-1.2 mu m at applied electric field frequencies of 200 Hz and 9.45 GHz. The dispersion of the clamped and unclamped electro-optic coefficients is measured and the fitted constants in the formula describing the clamped electro-optic coefficient dispersion are determined. The values of the clamped electro-optic coefficient dispersion are estimated. Based on the results of the measurements and reported data obtained from experiments on Raman scattering as well as on the measured second harmonic generation coefficient, an attempt has been made to estimate the value and dispersion of the electronic and ionic contributions to the nonlinear susceptibility.