Abstract

In this contribution we present a β-BaB₂O₄ optical parametric oscillator (OPO) that is pumped at 355 nm by a Q-switched single-axial mode pulsed Nd: YAG laser. The OPO, operated in a ring-cavity configuration, is injection seeded by a low power diode laser at 830 nm. The results of the injection seeding indicate a narrow-bandwidth output of the OPO at the signal (620 nm) and idler (830 nm) wavelengths. To stabilize the length of the OPO cavity, a Hänsch-Couillaud¹ locking mechanism is incorporated: the continuous light from the diode laser transmitted through the OPO cavity is used to optimize the cavity length. This stabilization technique is also used to sta­bilize external cavities in continuous laser systems.² The idler output of the OPO follows the same optical path as the diode laser (Fig. 1). To prevent disturbance of the locking mechanism by the idler light pulses, a chopper was placed in front of the lock box. With this scheme we are able to tune the seeded OPO, while keeping the cavity length optimized.

© 1994 IEEE