Analysis of third-order nonlinear susceptibilities of quadratic nonlinear optical crystals

The relations between the tensor components of the nonlinear susceptibilities responsible for self-action processes are measured in KDP, deuterated KDP, and LiNbO3 crystals at the Nd:YAG laser wavelength (lambda=1064 nm). The measurements are conducted on the basis of the analysis of the polarization dependences of focused radiation transmittance with the z-scan scheme. The obtained polarization dependences in KDP corresponded to the fourth-rank tensor of Kerr nonlinearity. The obtained values of nonlinear refractive indices are compared with the known experimental data.