Dispersion of the Nonlinear Optical Susceptibilityχ(3)inn-InSb in a Magnetic Field

A simple semiclassical model for the nonparabolic conduction band of InSb is used to calculate the third-order nonlinear optical susceptibility ${\chi }^{\mathrm{}\left(3\right)\mathrm{}}(-{\omega }_3, {\omega }_1, {\omega }_1, -{\omega }_2)$ in the presence of a dc magnetic field. In particular, we find resonant contributions when the difference frequency ${\omega }_2-{\omega }_1$ is near the cyclotron frequency or twice the cyclotron frequency. The results of this model are compared to earlier experimental results.