In-band diode pumped high power Ho:YLF laser

In this paper we present for the first time results on in-band pumping of a Ho:YLF laser using a GaSb laser diode stack with centre emission wavelength at 1930 nm as pump source. Ho:YLF is a very attractive laser material, because the lifetime of the upper laser level is much longer ( ~ 14 ms) than in Ho:YAG and the emission cross sections are higher. Additionally the thermal lens in Ho:YLF is much weaker, which helps to generate diffraction limited beams even under intense end-pumping.