Dispersion of|χ14(2)(ω1+ω2)|in GaAs and GaSb and of|χ14(2)(2ω)|in GaP in the optical region

Abstract

The second-harmonic optical nonlinear susceptibility $\left|{\chi }_{14}^{\mathrm{}\left(2\right)\mathrm{}}\right(2\mathrm{}{\omega }_1\left)\right|$ of GaP and the sum-frequency nonlinear susceptibility $\left|{\chi }_{14}^{\mathrm{}\left(2\right)\mathrm{}}\right({\omega }_1+{\omega }_2\left)\right|$ of GaAs and GaSb were measured by the reflected-harmonic method. The sources were a tunable dye laser in the energy range $1.2\le \hslash {\omega }_1\le 1.68$ eV, while $\hslash {\omega }_2=1.78\mathrm{}$ eV. Large dispersion of the nonlinear susceptibility was found in the vicinity of the $E_1$ transition energy in GaP. The spectra of $\left|{\chi }_{14}^{\mathrm{}\left(2\right)\mathrm{}}\right({\omega }_1+{\omega }_2\left)\right|$ and Miller's coefficient $\delta ({\omega }_1+{\omega }_2)$ in GaAs and GaSb were found to be similar to the same quantities in a second-harmonic-generation experiment. The nonlinear susceptibilities were also calculated using a simplified model proposed by Bell.