Numerical investigation of influence of the nonlinear refraction index upon the second harmonic generation

Abstract

Results of numerical analysis of the SHG dynamics by short intensive laser pulses in the crystals with the type I interaction are presented. The symmetrical split-step method was used for solution of the set of equations for the slowly varying complex amplitudes for the FH and SH including the group velocity mismatch, the beam diffraction, the phase mismatch, and the cubic nonlinearity of the Kerr-type medium. Applying this method, the main attention was paid to investigation of alteration of the spatio-temporal structure of the FH and the SH pulses, energy converson efficiency, and alteration of the beam propagation factors depending upon the group velocity and phase mismatch and upon diffraction and nonlinear lengths of the FH beam. The energy reconversion influenced by the nonlinear refraction index degrades significantly not only the enrgy conversion efficiency to the SH, but the beam quality as well.