A 20-W all-solid-state continuous-wave single-frequency source tuned to the sodium D<sub>2</sub>a line at 589.159 nm has been developed for adaptive optical systems. This source is based on sum-frequency mixing two injection-locked Nd:YAG lasers in lithium triborate in a doubly resonant external cavity. Injection locking the Nd:YAG lasers not only ensures single-frequency operation but also allows the use of a single rf local oscillator for Pound–Drever–Hall locking both the injection–slave and the sum-frequency cavities. We observe power-conversion efficiencies in excess of 55% and a linearly polarized diffraction-limited output tunable across the sodium D<sub>2</sub> line (589.156 to 589.160 nm) with no change in output power and with high amplitude and pointing stability.
© 2003 Optical Society of America
(010.1080) Atmospheric and oceanic optics : Active or adaptive optics
(010.7350) Atmospheric and oceanic optics : Wave-front sensing
(140.3520) Lasers and laser optics : Lasers, injection-locked
(190.2620) Nonlinear optics : Harmonic generation and mixing
(230.5750) Optical devices : Resonators
Joshua C. Bienfang, Craig A. Denman, Brent W. Grime, Paul D. Hillman, Gerald T. Moore, and John M. Telle, "20W of continuous-wave sodium D2 resonance radiation from sum-frequency generation with injection-locked lasers," Opt. Lett. 28, 2219-2221 (2003)