FEMTOSECOND OPTICAL PARAMETRIC OSCILLATORS - NUMERICAL STUDY ON PHASE-DEPENDENT PULSE FORMATION AND EXPERIMENTAL RESULTS

A numerical treatment of a synchronously pumped, single resonant optic al parametric oscillator in the saturation regime is developed. In our investigation we include a chi((3))-contribution of the nonlinear cry stal, take into account a particular optical resonator and apply an im proved treatment of the radial intensity distribution of the interacti ng fields. A telescope with a Kerr-medium and a hard aperture can be i nserted into the resonator to investigate Kerr-lens mode-locking of an OPO. A reasonable pump chirp or a n(2) comparable to the one of KTP r esults in a calculated pulse lengthening from 220 fs up to approximate to 300 fs. Experimental results on a single resonant optical parametr ic oscillator are presented with shortest pulses of 235 fs while the m easured shortening of the idler pulse with increasing intensity is in accordance to the calculations. (C) 1998 Elsevier Science B.V. All rig hts reserved.