Widely tunable in-band-pumped Tm:CaF2 laser

This Letter presents the efficient laser operation of a Tm:CaF2 crystal in-band pumped at 1610 nm by an Er-Yb-codoped fiber laser system. A laser slope efficiency of 55% (versus incident pump power) was achieved in a continuous-wave regime, with a maximum output power of 1.25 W at similar to 1.88 mu m in a nearly diffraction-limited beam (M-2 = 1.14). We also demonstrated a continuous tuning range of 180 nm, which extends to short wavelengths down to 1773 nm. (C) 2020 Optical Society of America