HIGHLY EFFICIENT PHASE-LOCKING AND EXTRACAVITY COHERENT COMBINATION OF 2 DIODE-PUMPED ND-YAG LASER-BEAMS

Intracavity phase locking and extracavity combination of the two emitt ed beams generated by a Nd:YAG laser longitudinally pumped by two fibe r-coupled diode lasers are investigated. Phase locking is performed by a diffractive component located inside a confocal Fabry-Perot resonat or. The coherent addition of the two synchronized beams in a single TE R loo wave is made by a birefringent interferometer, with 96.8% energy yield. 610-mW output power was obtained in a single-lobed beam profil e with 30.5% optical-to-optical conversion efficiency in the continuou s-wave regime. (C) 1996 Optical Society of America.