Dynamic behaviour of a doubly resonant optical parametric oscillator

Using a combination of computer modelling and experimental observation we have studied the dynamic behaviour of a doubly-resonant optical parametric oscillator (OPO). When pumped above threshold, it is observed that a finite time is required for the output of the OPO to be established. Specifically, for a doubly-resonant OPO based on KTP with a cavity length of 11 mm, pumped at 523 nm and phase-matched to give near degenerate output, we observe a build-up time for the OPO output of the order of 1 mu s. The observations are in excellent agreement with our numerical modelling and can be attributed completely to the time required for the OPO output to build-up from the parametric fluorescence.