High Power Diode-End-Pumped Nd:YAG 946-nm Laser and Its Efficient Frequency Doubling

We report a high power operation of the 4 F 3/2 → 4 I 9/2 transition in diode-end-pumped laser at 946 nm. The maximum output of 5.1 W is obtained with a short linear plano-concave cavity, and the slope efficiency is 24.5% at incident pump power of 23.3 W. To our knowledge, this is the highest value of the LD-pumped Nd:YAG 946 nm lasers that employ the conversional Nd:YAG rod as the gain medium. By intracavity frequency doubling with an LBO crystal, up to 982 mW cw output power in the blue spectral range at 473 nm is achieved at an incident pump power of 10.9 W with a compact three-element cavity, leading to optical-to-optical conversion efficiency of 9%. The conversion efficiency should be increased to 15.1%, if the rather low absorption coefficient of this Nd:YAG is considered.