High-power, air-cooled Thulium doped fiber amplifier with 71% slope efficiencyMathias Lenski, Qian Xu, Ziyao Wang, Philipp Gierschke, César Jauregui and Jens LimpertEPJ Web Conf., 307 (2024) 02047DOI: https://doi.org/10.1051/epjconf/202430702047