Calculation of Nonlinear Susceptibility Tensor Components in Ferroelectrics

Abstract

We present the formalism within which all second and third order nonlinear susceptibility coefficients can be calculated from the Landau expansion for an isotropic paraelectric phase by means of the Landau-Khalatnikov dynamical equations. Both first-order and second-order phase transitions are considered. Detailed results are given for all the second-order coefficients in the ferroelectric phase and for third harmonic generation, intensity-dependent refractive index and d.c. Kerr effect in both paraelectric and ferroelectric phases.