Pulsed Single-Frequency Polarization-Maintaining Holmium Laser at 2050 & 2090 nm D. Lorenz, C. Romano, M. Eichhorn and C. Kieleck EPJ Web Conf., 243 (2020) 22001 Published online: 15 October 2020 DOI: 10.1051/epjconf/202024322001