Peculiarities of non-linear spectroscopic ellipsometry of initially isotropic substances

Abstract We present novel non-linear spectroscopic techniques for the advantageous determination of the third-order complex susceptibility as well as spectroscopic parameters of isotropic media which exhibit light-induced anisotropy. These methods are quite simple and general and can be applied to a large variety of substances. Optically heterodyned polarization spectra have been obtained for dye solutions for the first time. They exhibit light-induced dichroism and birefringence within the absorption band.