∼1 mJ pulsed vortex laser at 1645 nm with well-defined helicity

We report on a millijoule level Er:YAG ceramic pulsed vortex laser resonantly pumped by an annular beam at 1532 nm. By means of an uncoated YAG crystal plate inserting into the cavity and a proper thermal gradient on the ceramic, 1.03 mJ LG(0,-1) mode and 0.97 mJ LG(0, + 1) mode were respectively produced, and no vortex mode instability problem was observed. We believe the directly generated millijoule level optical vortex with well-defined helicity will have potential applications in material modification and processing, high-field laser physics, and nonlinear optics, etc. (C) 2016 Optical Society of America