Growth and spectroscopic properties of the 2.9 μm Tm,Ho:LuYAG laser crystals

Lu2.4Y0.6Al5O12 (LuYAG) crystals with three different doping concentrations of Tm3+ and Ho3+ 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 mu m, suggesting that the Tie ions can act as the sensitizer for Ho3+ ions. The stimulated emission cross-sections at 2.911 mu m are calculated to be 5.49 x 10(-18) cm(2), 3.11 x 10(-18) cm(2), and 4.04 x 10(-18) cm(2), respectively. Compared with the Tm,Ho:LuAG, and Tm,Ho:YAG crystals, the Tm,Ho:LuYAG crystal with 3 at.% Tm3+ and 1 at.% Ho3+ has a relatively longer lifetime 0.138 ms for the upper level I-5(6) and a shorter lifetime 7.25 ms for the lower level I-5(7), which is advantageous to the population inversion. These results indicate that the Tm,Ho:LuYAG crystal with 3 at.% Tm3+ and 1 at.% Ho3+ is a new potential candidate for realizing the 2.911 mu m laser output. (C) 2015 Elsevier B.V. All rights reserved.