100 W orbital angular momentum laser at 2 µm

Direct power scaling of an at-source scalar orbital angular momentum (OAM) laser is demonstrated in a Ho:YAG single-crystal fiber (SCF). Benefiting from the long gain region and the large surface-to-volume ratio of this fiber-like geometric structure, a 100 W optical vortex laser (OAM = ℏ) with a high slope efficiency of 66.0% is achieved at 2.1 µm, which is, to the best of our knowledge, the record power of the at-source OAM laser in the 2 µm spectral range and opens a new route for direct generation of high-power, high-efficiency structure light beams.