ABSTRACT
Nonlinear refraction is the cause of several important effects on laser beam propagation in optical materials. These effects, some of which are desirable and some undesirable, are caused by the dependence of the refractive index of a medium on the local optical irradiance. The initial interest in the nonlinear refractive index was generated by its detrimental effects on laser pulse propagation. The scope of the references cited and the new data compiled in this article is limited to work on the “fast” electronic and optical vibrational contributions to n2 in insulating crystals and glasses and in large-band gap semiconductors. The experimentally obtained hyperpolarizabilities for fluorine and oxygen ions were found to scale in a simple way with cation radius, and evidence was obtained for the additivity of anion-cation pair hyperpolarizabilities for crystals of different structures and compositions.
