- Nicolas Forget: Laboratoire Aimé Cotton, Centre National de la Recherche Scientifique, UPR 3321, Campus d'Orsay, Bâtiment 505, 91405 Orsay, France., and O nicolas.forget@polytechnique.fr
We report on what we believe to be the first demonstration of active mode locking of an optical parametric oscillator. An acousto-optic modulator is inserted into a nearly degenerate (approximately 1064 nm) and doubly resonant optical parametric oscillator based on periodically poled LiNbO3 and pumped with the second harmonic of a quasi-continuous-wave single-frequency Nd:YAG laser. When the modulation frequency is matched to the free spectral range of the cavity (120 MHz), a pulsed regime is observed, with pulse durations as short as 700 ps.