Growth and spectroscopic investigations of Yb,Ho: YAP and Yb,Ho,Pr:YAP laser crystals

Yb,Ho:YAP and Yb,Ho,Pr:YAP laser crystals with high optical quality are successfully grown using the Czochralski method. The absorption coefficient and band width of the two crystals at 970nm are increased because of the doping of Yb3+ sensitizer. The three strongest fluorescence peaks of the two crystals are located at approximately 2844, 2853, and 2912nm, which correspond to the 5I6→5I7 level transitions of Ho3+ ions. Lifetime measurements indicate that the deactivator Pr3+ ions can efficiently decrease the lifetime of the lower level 5I7 from 8.848ms to 1.258ms. Energy-transfer mechanisms are also studied and analyzed, and up-conversion luminescence spectra provide the further evidence that Pr3+ ions can efficiently depopulate Ho3+ ions at the 5I7 level. All these results show that Yb,Ho,Pr:YAP crystal may be a promising laser medium for realizing 2.8–3.1μm lasers pumped using a 970nm laser diode. •New Yb,Ho:YAP and Yb,Ho,Pr:YAP laser crystals are grown by the CZ method.•The absorption and FWHM at 970nm are increased due to the doping of Yb sensitizer.•The lifetime of lower laser level 5I7 decreases from 8.848 to 1.258ms because of the doping of Pr3+ deactivator.•The up-conversion luminescence provides the further evidence that Pr3+ ions can efficiently depopulate Ho3+ ions at the 5I7.•The Yb,Ho,Pr:YAP crystal may be a promising laser medium for realizing the 2.8–3.1μm lasers using 970nm LD.