Efficient high-power laser operation of Yb:KLu(WO_4)_2 crystals cut along the principal optical axes

Abstract

High-power continuous-wave laser operation was demonstrated with $\mathrm{Yb}:\mathrm{K}\mathrm{Lu}{\left(\mathrm{W}{\mathrm{O}}_4\right)}_2$ crystals cut along the $N_p$, $N_m$, and $N_g$ principal optical axes, achieving a nearly equal slope efficiency of 79%–80% in the absence of thermal effects. The $N_g$-cut crystal proved to be the most advantageous for power scaling as well as efficient pumping. A maximum output power of $11.0\mathrm{W}$ was produced from a $2\mathrm{mm}$ thick uncoated $N_g$-cut crystal in a $\sim 7\mathrm{mm}$ long plano–concave resonator end pumped by a fiber-coupled diode; the corresponding optical-to-optical efficiency was 68%.