Highly efficient Er:YAP laser with 6.9 W of output power at 2920 nm

We report on the efficient high-power operation of a laser-diode-pumped Er³⁺-doped yttrium aluminum perovskite (Er:YAP) laser in the 3 μm spectral region at room temperature. 6.9 W of continuous-wave (CW) output power was obtained at 2920 nm. The slope efficiency was as high as 30.6% with respect to the absorbed pump power, which is close to the quantum defect limit (33.4%). To the best of our knowledge, this is the highest CW output power generated from 3 μm Er³⁺-doped solid state lasers at room temperature. Furthermore, our analysis has shown that more than 10 W of output power based on Er:YAP is possible by further mitigating the thermal lens effect.