Recent Progress in Laser Crystals and Ceramics for Femtosecond Mode-Locked Lasers at ~2 μm [Invited] Pavel Loiko, Weidong Chen, Xavier Mateos, Patrice Camy, Uwe Griebner and Valentin Petrov EPJ Web Conf., 267 (2022) 01030 Published online: 18 October 2022 DOI: 10.1051/epjconf/202226701030