Efficient diode-pumped intracavity frequency-doubled CWNd : YLF laser emitting at 656 nm for a silver atom optical clock

Ultraviolet single mode laser light is proposed by frequency quadrupling the output of a Nd:YLF laser with two successive frequency doubling stages. For a simple linear cavity laser configuration investigated at 1312nm, we have obtained an intracavity powe of 310 W for 16 W of absorbed pump power (lambda(p) similar to 806 nm). Up to 10mW tunable single-frequency laser (lambda(2 omega) = 656-658 nm) is observed. This has been achieved by intracavity second-harmonic generation of a diode-pumped Nd:YLiF4 linear laser oscillating on the sigma-polarized F-4(3/2)-I-4(13/2) transition (lambda(omega) similar to 1314 nm) with a beta-Barium Borate (BBO) crystal. We also report the experimental measurement of the red-uv conversion efficiency according to the waist size in the BBO crystal. Obtained value is compared to those given by the Boyd-Kleinman theory.