Investigations on a New Laser Medium of 2 µm: Tm3+, Ho3+ Co-Doped Y3Ga5O12 Crystal

A thulium and holmium (Tm, Ho) co-doped Y 3 Ga 5 O 12 (Tm:Ho:YGG) single crystal has been cultivated for the first time to the best of our knowledge by the optical floating zone method. Then the crystal structure has been analyzed by X-ray powder diffraction, and its thermodynamic properties have been determined. Its absorption and fluorescence spectra have been measured. By the reciprocity principle (RM) and Fuchtbauer–Ladenburg (F–L) formula, the emission cross-sections of Ho 3+ ( 5 I 7 → 5 I 8 ) have been calculated. A continuous-wave (CW) Tm:Ho:YGG laser has been constructed with a maximum output of 1.325 W and an optical conversion efficiency of 10.8% at a wavelength of 2086 nm. All our results have shown that Tm:Ho:YGG should be an excellent material for use in 2 μm lasers.