Abstract

Passive optical locking of an 865-nm diode laser to a standing wave, external resonator containing potassium niobate has resulted in efficient harmonic generation at 432 nm.¹ Our most recent experiments have yielded 1.5 mW of unidirectional blue output (3.0 mW total) at an input power level of 15 mW. The measured intracavity infrared buildup factor of >100 in these experiments indicated that total absorption and scattering losses within the resonator were below 1% and that >90% of the incident power was matched into the fundamental mode of the resonator. As demonstrated by Kozlovsky,² further improvements in unidirectional conversion efficiency are possible by using a traveling wave ring cavity in place of a standing wave resonator. The use of a ring cavity also eliminates the need for optical isolation between the external cavity and the source laser. In this paper we describe a SLEDD laser in which a ring resonator is used to build fundamental power. Passive locking is accomplished by imaging the cavity throughput back onto the diode laser.

© 1989 Optical Society of America