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Lu 2.4 Y 0.6 Al 5 O 12 (LuYAG) crystals with three different doping concentrations of Tm 3+ and Ho 3+ were grown successfully by the Czochralski method. The crystals exhibit broad absorption band at 783 nm and the full width at half maximum (FWHM) are about 11 nm. Excited by 783 nm laser diode (LD), strong fluorescence peaks are observed near 2.9 μm, suggesting that the Tm 3+ ions can act as the sensitizer for Ho 3+ ions. The stimulated emission cross-sections at 2.911 μm are calculated to be 5.49 × 10 −18 cm 2 , 3.11 × 10 −18 cm 2 , and 4.04 × 10 −18 cm 2 , respectively. Compared with the Tm,Ho:LuAG, and Tm,Ho:YAG crystals, the Tm,Ho:LuYAG crystal with 3 at.% Tm 3+ and 1 at.% Ho 3+ has a relatively longer lifetime 0.138 ms for the upper level 5 I 6 and a shorter lifetime 7.25 ms for the lower level 5 I 7 , which is advantageous to the population inversion. These results indicate that the Tm,Ho:LuYAG crystal with 3 at.% Tm 3+ and 1 at.% Ho 3+ is a new potential candidate for realizing the 2.911 μm laser output. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new Cr,Yb,Ho,Eu:YAP laser crystal was grown by the CZ method for the first time. [•] Thermal properties indicate the suitable crystal growth direction is the b axis. [•] Spectroscopic measurements show Cr3+ and Yb3+ can act as sensitizers of Ho3+ ions. [•] Eu3+ ions can act as deactivator in decreasing threshold and increasing efficiency. [ABSTRACT FROM AUTHOR]