Tm-doped LiLuF4 crystal for efficient laser action in the wavelength range from 1.8 to 2 µm

Room-temperature continuous-wave laser action in a novel Tm-doped LiLuF4 crystal emitting at around 1.9 µm is demonstrated. The crystal growth process, spectroscopic measurements, and laser performance are presented for different Tm concentrations. An overall tunability extending from 1817 to 2056 nm, a slope efficiency of 46%, and a maximum output power in excess of 1.1 W are reported.