Growth, spectral characteristics, and laser performance of Yb: Lu3Ga5O12 crystals

High quality Yb-doped LuGG single crystal with dimensions of & Oslash;30 mm x 50 mm was successfully grown by the Czochralski method, and its growth, spectral characteristics, and laser performance were studied. Absorption spectra, fluorescence spectra, and fluorescence lifetime were measured at room temperature and low temperature (8 K). The absorption cross section, oscillator strength, line strength, transition probability, and radiative lifetime of Yb:LuGG were calculated. The lifetimes of excited energy level F-2(5/2) of Yb(3+)were determinded under different experimental conditions. The experimental lifetime of Yb:LuGG is consistent with calculated value very well. The emission cross section was calculated to be 2.11 x 10(-20) cm(2), which is higher than that of the common laser crystal Yb:YAG. The spin-orbit parameters and intrinsic crystal field parameters (CFP) of Yb:LuGG were fitted by the superposition model (SM) with good consistency between calculated and experimental crystal field levels. Additionally, the laser performance parameters were calculated, and the maximum output power of 2.57 W was obtained with a slope efficiency of 12.16 %. All results indicate that Yb:LuGG crystal is a highly promising laser crystal material.