Slope efficiency measurements of a chromium-doped forsterite laser

The slope efficiency of the continuous-wave chromium-doped forsterite (Cr:Mg(2)SiO(4)) laser has been measured by using four different output mirrors. The maximum slope efficiency of 38% was achieved with an 11% output coupler. The extrapolated limiting slope efficiency in the absence of passive losses is estimated to be 65%. This value corresponds to an intrinsic quantum efficiency of 77%, which is similar to the efficiencies determined for mature tunable solid-state laser systems.