Growth and fluorescence characteristics of Er:LuAG laser crystals

Er-doped Lu₃Al₅O₁₂ (Er:LuAG) single crystals with various doping concentrations of 0.2, 0.5, 1.0, and 3.5 at% are grown by the Czochralski method. In the growth process, the cracking problem of this refractory crystal is overcome by a modified temperature field. Then, the lattice parameters and dopant segregation coefficient of as-grown boules are revealed. In addition to the structure and components, we mainly focus on the absorption and fluorescence spectra of Er:LuAG. Specifically, the absorption ranging from 250 to 1700 nm presents the characteristic energy-levels of the Er dopant. Using a 970 nm pump laser, strong fluorescence peaks are observed at 1532 nm, indicating Er:LuAG is an outstanding potential laser material in both the human eye-safe band and long air-path transmission. Notably, the best results were observed at an Er concentration of 1 at% with the highest luminescence intensity.