Spectroscopic and laser properties of Er:LuSGG crystal for high power ∼28 μm mid-infrared laser

We demonstrate a novel Er:LuSGG active gain medium emitting laser wavelength at 2795 nm for the first time. The Er:LuSGG crystal is grown successfully by the Czochralski method with high crystalline and optical quality. The spectra properties, including absorption and fluorescence emission cross-section are presented in contrast with similar Er-doped garnet crystals. The fluorescence lifetimes of the upper (4I11/2) and lower (4I13/2) laser levels are 1.75 and 4.64 ms, respectively. Under 973 nm laser diode pumping, a maximum output power of 789 mW in continuous-wave mode, corresponding to optical-to-optical efficiency of 20.2% and slope efficiency of 24.4%, is achieved with high laser beam quality. The results show that the Er:LuSGG is a promising MIR laser material operated at 2.8 µm.