caa a22 4500 445368713 CHVBK 20180317142939.0 cr unu---uuuuu 170323e20110601xx s 000 0 eng 10.1007/s00340-011-4467-6 doi (NATIONALLICENCE)springer-10.1007/s00340-011-4467-6 Schellhorn M. French-German Research Institute of Saint Louis ISL, 5 rue du Général Cassagnou, 68301, Saint-Louis, France aut A comparison of resonantly pumped Ho:YLF and Ho:LLF lasers in CW and Q-switched operation under identical pump conditions [Elektronische Daten] [M. Schellhorn] Singly 0.5 at.% Ho doped crystals of YLiF4 (YLF) and LuLiF4 (LLF) are studied under identical pump conditions in continuous-wave (CW) and Q-switched operation. Longitudinal end-pumped CW laser performance shows Ho:LLF to have a slightly lower threshold and a slightly higher slope efficiency with respect to absorbed pump power than Ho:YLF. Both lasers were operated on π-polarization. At a cavity output coupling of 20% and a crystal length of 30mm, the Ho:LLF (Ho:YLF) laser yielded 18.8W (18W) of CW output at a wavelength of 2067.8nm (2064.0nm) for 41.4W (42.2W) of absorbed pump power with a slope efficiency of 67.1% (65.6%) and an optical-to-optical efficiency of 45.4% (42.6%) with respect to absorbed pump power. With the same output coupling and a crystal length of 40mm, the Ho:LLF (Ho:YLF) laser yielded 20.5W (18.1W) of CW output at a wavelength of 2067.7nm (2064.3nm) for 51.5W (50.0W) of absorbed pump power with a slope efficiency of 58.4% (55.4%) and an optical-to-optical efficiency of 39.8 (36.1%) with respect to absorbed pump power. The influence of the temperature of the cooling mount on CW laser performance was studied and showed very similar results for both laser materials. At full pump power, a slope of −155mW/°C (−149mW/°C) was observed for the Ho:LLF (Ho:YLF) laser with a crystal length of 30mm. In Q-switched operation, the Ho:LLF (Ho:YLF) laser produced 37mJ (38.5mJ) at a repetition rate of 100Hz with a pulse duration of 38ns (35ns) at a wavelength of 2053.1 nm (2050.2nm) with a slope efficiency of 30.3% (31%) and an optical-to-optical efficiency of 14.2% (13.9%) with respect to absorbed pump power. The beam quality was nearly diffraction limited (M 2<1.1). Springer-Verlag, 2011 Applied Physics B Springer-Verlag 103/4(2011-06-01), 777-788 0946-2171 103:4<777 2011 103 340 https://doi.org/10.1007/s00340-011-4467-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00340-011-4467-6 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Schellhorn M. French-German Research Institute of Saint Louis ISL, 5 rue du Général Cassagnou, 68301, Saint-Louis, France aut NATIONALLICENCE 773 0- Applied Physics B Springer-Verlag 103/4(2011-06-01), 777-788 0946-2171 103:4<777 2011 103 340 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer