Second harmonic pulse distortion by imperfect phase matching

We report on the distortion of second harmonic pulses generated in non-phase-matched conditions by highly efficient nonlinear crystals. the effect depends strongly on the temporal and spatial profiles of the incident fundamental pulse and on the phase mismatch. A Q-switched and mode-locked Nd:YAG laser was employed to demonstrate several temporal and spatial shapes for the second harmonic pulse train produced by a KTP crystal. (C) 2000 Elsevier Science B.V. All rights reserved.Universidade Federal de São Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP, BrazilUniversidade Federal de São Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP, BrazilWeb of Scienc