ORIENTATIONAL PROPERTIES OF THE 3RD-ORDER NONLINEAR POLARIZATION FOR DEGENERATE OPTICAL INTERACTIONS IN ZINCBLENDE SEMICONDUCTORS

The orientational dependence of the third order nonlinear optical pola rization density for degenerate optical interactions in zinc-blende se miconductors has been derived, corresponding to two-photon absorption and Kerr refraction. A specific emphasis is put on the role of the ani sotropic property of the third order optical susceptibility in optical interactions. Significant modulations by the anisotropy on the induce d polarization densities are demonstrated for situations of single- an d two-beam irradiation. The reduced forms in the isotropic limit are d iscussed as well. Furthermore for two-beam irradiation in the isotropi c limit, we have determined numerical factors of 2 and 2/3 for cross-m odulations corresponding to parallel and orthogonal polarizations of t he two waves, respectively, with respect to self-modulation.