Nonlinear refraction of dielectric single crystals under excitation with ultrashort near-infrared laser pulses

Nonlinear refraction in a number of crystals (KGW, KGW:Eu$^{3+}$, Ba(NO$_{3}$)$_{2}$, BaWO$_{4}$, PbMoO$_{4}$, CdWO$_{4}$) that are promising for excitation of multifrequency stimulated Raman scattering is investigated by a single-beam Z-scan method. Picosecond laser pulses with a wavelength of 1064 nm generated by a YAG:Nd$^{3+}$ laser were used for excitation of nonlinear optical processes. The values of $n_2$ are compared depending on the type of the crystal, optical-axis orientation, and impurity concentration.