Thermal, spectroscopy and optimized ∼3 µm CW laser properties for Ho,Pr:YAP crystal

We demonstrate the thermal, spectroscopy and laser properties of Ho,Pr doped YAP crystal grown successfully by Cz method. The thermal expansion coefficient, thermal conductivity, absorption and emission spectra of Ho,Pr:YAP crystal are investigated in detail. Additionally, the level lifetimes suggest that Pr³⁺ is a suitable deactivating ion for Ho:YAP crystal. Particularly, the actual laser performance is optimized by doping active ion Ho with high concentrations and introducing deactivated Pr³⁺, resulting in decreased laser threshold, increased laser output power and slope efficiency. A 3.01 µm laser with output power of 502 mW, slope efficiency of 6.3% and beam quality factors of 1.42/1.43 is achieved in the Ho,Pr:YAP crystal, as far as we know this is the highest ∼3 µm CW laser power realized in Ho³⁺ doped oxide crystals.