ORIENTATIONAL PROPERTIES OF THE THIRD ORDER NONLINEAR POLARIZATION FOR DEGENERATE OPTICAL INTERACTIONS IN ZINC-BLENDE SEMICONDUCTORS
The orientational dependence of the third order nonlinear optical polarization density for degenerate optical interactions in zinc-blende semiconductors has been derived, corresponding to two-photon absorption and Kerr refraction. A specific emphasis is put on the role of the anisotropic property of the third order optical susceptibility in optical interactions. Significant modulations by the anisotropy on the induced polarization densities are demonstrated for situations of single- and two-beam irradiation. The reduced forms in the isotropic limit are discussed as well. Furthermore for two-beam irradiation in the isotropic limit, we have determined numerical factors of 2 and 2/3 for cross-modulations corresponding to parallel and orthogonal polarizations of the two waves, respectively, with respect to self-modulation.