High-energy 2  µm pulsed vortex beam excitation from a Q-switched Tm:LuYAG laser.

We report on the first, to the best of our knowledge, direct generation of pulsed vortex beams at 2 mu m from a Q-switched Tm:LuYAG laser. High-energy Laguerre-Gaussian (LG(0,l)) pulsed laser beams with well-defined handedness are selectively excited through spatially matched pump gain distribution and asymmetric cavity loss without using any intracavity handedness-selective optical elements. Pulse energies of 1.48 mJ for the LG(0,) (+1) mode and 1.51 mJ for the LG(0,) (-1)mode, respectively, are achieved at a repetition rate of 500 Hz. The pulsed laser beams with helical wavefronts are potentially useful for studying orbital angular momentum transformation dynamics, generation of mid-IR vortex beams, and nanostructuring of organic materials. (C) 2020 Optical Society of America