Growth, Optical, and Laser Properties of Large-Sized Cr,Nd:Y₃Al₅O₁₂ Crystal

The growth and characterization of Cr,Nd:Y₃Al₅O₁₂ (YAG) crystal are reported. By improving the synthesis and sintering processes of polycrystalline materials, as well as the temperature gradient and annealing atmosphere, a high quality crystal with size of ϕ30 mm × 110 mm is obtained by using the Czochralski technique. After measuring the concentrations of dopant Cr³⁺ and Nd³⁺ within the different parts of the grown crystal, it is found that the distribution of dopant ions is uniform throughout the crystal. The fluorescence spectra of Cr,Nd:YAG crystal exhibit intense emissions at 1064 nm under excitations of 808 and 450 nm. The fluorescence lifetime of Nd: ⁴F_3/2 level is obtained to be 234.2 µs. The maximum average output power reaches 7.87 W with a slope efficiency of 31.2% for near-infrared laser at 1063.9 nm. The above results indicate that Cr,Nd:YAG crystal is a promising gain media for all-solid state lasers.