Investigation of Erbium-doped YScO₃ and GdScO₃ crystals as potential hosts for ∼1.6 μm lasers

Erbium-doped oxide crystals are extensively applied as gain medium of eye-safe wavelength lasers. In this study, we systematically investigated spectroscopy properties of ∼1.6 μm waveband in Er³⁺-doped rare-earth oxide crystals YScO₃ and GdScO₃, which were grown with Edge-defined Film-fed Growth (EFG) technique. By employing high-power 1532 nm laser excitation, we examined the effects of doping concentration and crystal structure on up-conversion losses, as demonstrated by power-dependent up-conversion emissions across different crystals. Furthermore, temperature-dependent spectral analyses revealed the disordered structural characteristics of YScO₃ crystal. In conclusion, 0.25 %Er:YScO₃ proves to be a more promising laser host for resonantly pumped ∼1.6 μm laser applications in consideration of reduced up-conversion loss.