Femtosecond optical parametric oscillators: numerical study on phase-dependent pulse formation and experimental results

Abstract

A numerical treatment of a synchronously pumped, single resonant optical parametric oscillator in the saturation regime is developed. In our investigation we include a χ (3)-contribution of the nonlinear crystal, take into account a particular optical resonator and apply an improved treatment of the radial intensity distribution of the interacting fields. A telescope with a Kerr-medium and a hard aperture can be inserted 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 results in a calculated pulse lengthening from 220 fs up to ≈300 fs. Experimental results on a single resonant optical parametric oscillator are presented with shortest pulses of 235 fs while the measured shortening of the idler pulse with increasing intensity is in accordance to the calculations.