Lu3Ga5O12 crystal: exploration of new laser host material for the ytterbium ion

A ytterbium (Yb) doped lutetium gallium garnet (Yb:Lu3Ga5O12, Yb:LuGG) single crystal has been successfully grown by the optical floating-zone method for the first time to our knowledge. Its thermal properties, including specific heat, thermal expansion coefficient, and thermal diffusion coefficient, were measured, and the thermal conductivity was determined to be 4.94 Wm(-1) K-1 at room temperature. The absorption and fluorescence spectra were measured at room temperature. The stimulated emission cross-sections were calculated using the reciprocity method and Fuchtbauer-Ladenburg formula, respectively. Continuous-wave (CW) laser oscillation of the Yb:LuGG crystal was also demonstrated with a 971 nm diode laser used as the pump source, generating an output power of 3.1 W with a slope efficiency of 44%. The results of our study indicate that the Yb: LuGG crystal is a promising new laser medium, and it is expected to be comparable to the most widely used material, Yb:YAG. (c) 2012 Optical Society of America