Highly efficient 110-W closed-cycle cryogenically cooled Nd:YAG laser operating at 946 nm

We report a new, to the best of our knowledge, record power and efficiency for a 946 nm Nd:YAG laser, producing > 110 W ( 5 T W m − 2 s r − 1 ) with a slope efficiency of 80%, with respect to absorbed pump power, and an optical-to-optical efficiency of 74%, with respect to incident power. To achieve this performance, we utilized a closed-cycle acoustic Stirling cryostat to maintain the gain medium temperature at ∼ 80 K and direct in-band pumping with a volume-Bragg-grating stabilized diode laser bar operating at 868 nm. Daily operation, including cycling of the laser crystal temperature, akin to a comparable water-cooled solid-state laser system, is demonstrated.