A 200 W INNOSLAB Tm:YLF laser

We report obtaining 200 W of continuous wave laser emission at 1.9 mu m from an INNOSLAB Tm: YLF (YLiF4) laser. The slope efficiency is 52.2% with respect to the absorbed pump power. The wavelength of the laser output and the polarization direction can be switched between 1890 and 1908 nm. Due to the stable resonator design in both axes of the slab crystal, the output is strongly elliptical with a Gaussian distribution beam shape along the semi-minor axis and a top-hat-like distribution beam shape along the semi-major axis. This laser source is ideal for pumping a holmium-doped slab crystal in a pulsed INNOSLAB amplifier.