PHASE-DRIVEN PULSE BREAKING DURING PERFECTLY-MATCHED 2ND-HARMONIC GENERATION

A frequency-domain description of the second-harmonic generation by us ing laser pulses is presented. The influences of the pulse spectrum an d of the crystal dispersion are taken into account which, for high int ensities at perfect phase-matching can produce stretching and eventual ly breaking of the pulse. A double autocorrelator has bern constructed tu monitor the pulse breaking during perfectly-matched second harmoni c generation in a type I KDP crystal. A double passage inside the crys tal was necessary to measure the nonlinear phase that the fundamental beam experiences during the first generation. (C) 1998 Elsevier Scienc e B.V.