Local field cascading in third-order non-linear optical phenomena of liquids

Contributions to the third-order non-linear polarization response of molecular liquids due to cascaded second-order processes are discussed. The cascading occurs entirely because of the presence of a reaction field to the second-order polarization of non-centrosymmetric molecules. Application of a simple dielectric continuum model is used to investigate relative magnitudes, polarization anisotropy and resonance behavior.