Diode-pumped Pr^3+:LiYF_4 continuous-wave deep red laser at 698 nm

Abstract

We report continuous-wave laser operation at 698 nm in ${\mathrm{Pr}}^{3+}$-doped ${\mathrm{LiYF}}_4$ crystal using an InGaN laser diode emitting at 444 nm with a maximum output power of 760 mW. By suppressing the oscillation at 640 and 721 nm, a maximum output power of 156 mW at 698 nm was obtained in a single transverse mode with a slope efficiency as high as 48.7%. The beam quality factors $M^2$ in the $x$ and $y$ directions were measured to be 1.4 and 1.2, respectively.