Anisotropy of the nonlinear susceptibility of cadmium sulfide crystals

The self-interaction methods were used to determine an anisotropy of the cubic nonlinear susceptibility χ⁽³⁾ and of the nonlinear susceptibility of the fifth order in the fields χ⁽⁵⁾ of CdS crystals in a wide spectral range. An anomalously strong anisotropy of the nonlinear susceptibility χ⁽⁵⁾ was observed in the region of the fundamental absorption edge and it was attributed to an anisotropy of the two-photon absorption coefficient which represented a resonance contribution of intermediate exciton states. This extremely large anisotropy of χ⁽⁵⁾ was used to record polarization holograms.