Spectroscopy and laser operation of Er doped YScO sesquioxide crystals at 2.8 µm.

Growth, spectroscopy, and laser experiments of the Er:YScO crystals at 2.8 µm are presented. The high-quality Er:YScO crystals were grown by the optical floating zone method. We reveal the structural disorder of Er:YScO crystal and the thermal conductivities of as-grown crystals for different temperatures. The absorption spectra, emission spectra, fluorescence lifetimes, and gain spectra were investigated. The Er:YScO crystal features broader absorption bandwidth induced by disordered crystal structure with an absorption cross section σ of 3.2 × 10 cm at 981 nm and a maximum emission cross-section σ of 1.34 × 10 cm at 2714 nm. The Er:YO has the larger spectral quality factor of 3.25 × 10ms·cm and higher thermal conductivity among as-grown crystals illustrating great potential for high-power laser output at 2.8 µm. Under an absorbed pump power of 9.77 W, a maximum laser output power of 972 mW with a slope efficiency of 10.4% in Er:YO crystal was obtained.