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

We report on the growth and laser operation of Tm:Lu3Al5O12 (Tm:LuAG) single crystal grown via the micro-pulling-down ($\mu $ -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 $21.9~\mu \text{J}$. This letter reveals that the $\mu $ -PD technique is reliable for growing high-performance Tm3+-doped crystals for various potential applications. [ABSTRACT FROM AUTHOR]