Laser Operation in a Tm:LuAG Crystal Grown by the Micro-Pulling-Down Technique

We report on the growth and laser operation of Tm:Lu
₃
Al
₅
O
₁₂
(Tm:LuAG) single crystal grown via the micropulling-down (μ-PD) method, for the first time to the best of our knowledge. Spectral properties (absorption and fluorescence) and fluorescence lifetime of the Tm:LuAG crystal were measured at room temperature. Using a 790-nm diode laser as pump source, continuous-wave laser operation of the Tm:LuAG crystal was demonstrated with a maximum output power of 2.88 W and a slope efficiency of about 39.1% at 2016 nm. Passively Q-switched laser operation was also investigated using Cr:ZnSe as saturable absorber. The maximum average output power reached about 0.53 W with the shortest pulse width of 54.3 ns and a pulse energy of 21.9 μJ. This letter reveals that the μ-PD technique is reliable for growing high-performance Tm
³⁺
-doped crystals for various potential applications.