Diode-Pumped Compact cw Frequency-Doubled Nd:YAG Laser in the Watt Range at 473 nm

We report a diode-pumped cw Nd:YAG laser operating on the ⁴F_3/2-⁴I_9/2 transition at 946 nm, for which a maximum output power of 4.5 W with a slope efficiency of 21% is achieved at an incident pump power of 26 W. Two LiB₃O₅ (LBO) crystals of different lengths (3 x 3 x 10 mm and 3 x 3 x 15 mm), cut for critical type I phase matching at room temperature, have been used for intracavity frequency doubling, and through optimization of the structure and elements of the cavity, a maximum single-ended blue output power of 1.1 W has been obtained with an optical conversion efficiency of 4.2%. A stability better than 4.8% with no mode hopping over a period of 2 h has been achieved.