Dual Pulse Operation of 1.5 μm Picosecond Intracavity Synchronously Pumped Optical Parametric Oscillator

Singly resonant optical parametric oscillators (OPO) are most promising approach to sensors in which two pulses circulate independently in a cavity. The OPO should be pumped intracavity, not only to access the high intracavity power of the pump laser, but also because the two signal pulses share the same mode. The first synchronously pumped OPO were pumped intracavity by a mode-locked dye laser. Subsequent implementation with solid-state pump lasers has been plagued by a tendency to Q-switching, as well as competition between the two pulses generated in the signal cavity. In this contribution we report the improved and optimized experimental setup of an intracavity synchronously pumped OPO based on a periodically poled LiNbO3 crystal (PPLN) and of the pumping resonator of passively mode locked Nd:YVO4 laser from the point of view of achievability of stable mode-locking and compensation of the astigmatism caused by Brewster angle cut PPLN. This resulted in higher conversion efficiency due to the good overlap of pump and signal beam.