Output-coupling-dependent laser operation of monoclinic Yb:Ca4LaO(BO3)3 crystal

We have studied the laser operation of Yb:LaCOB crystal for what we believe is the first time. Adopting a plane-concave cavity, the laser properties were measured for the X-cut, Y-cut, and Z-cut crystals. The best output power of 3.2 W was obtained with a slope efficiency 69.90% by employing the Y-cut crystal. A more efficient operation with slope efficiency of 82.31% was realized for the X-cut crystal, with the output power of 2.0 W. The laser spectra were collected under the absorbed pump power of 3.9 W for X cut and Z cut and 6.7 W for Y cut. The emission wavelengths were dependent of the transmittance of output couplers.