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 Yb:KLu(WO(4))(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 W was produced from a 2 mm thick uncoated N(g)-cut crystal in a approximately 7 mm long plano-concave resonator end pumped by a fiber-coupled diode; the corresponding optical-to-optical efficiency was 68%.