8.7-W average power femtosecond Ho:CALGO bulk laser at 2.1 μm Weichao Yao, Yicheng Wang, Sergei Tomilov, Shahwar Ahmed, Christoph Liebald, Daniel Rytz, Mark Peltz, Volker Wesemann and Clara J. Saraceno EPJ Web Conf., 267 (2022) 01054 Published online: 18 October 2022 DOI: 10.1051/epjconf/202226701054