Optical absorption and photoluminescence in Sm³⁺- and Eu ³⁺-doped rare-earth borate glasses

Sm³⁺- and Eu³⁺-doped rare-earth borate glasses (Li₂O-BaO-La₂O₃-B₂O₃) have been fabricated and characterized optically. The density, refractive index, optical absorption, Judd-Ofelt parameters, and spontaneous transition probabilities have been measured, calculated and analyzed. Sm³⁺ and Eu³⁺ emit intense reddish-orange and red lights under blue and UV light excitations, respectively. In Sm³⁺ and Eu³⁺ co-doped glasses, the excitation wavelength range of Eu³⁺ emission is broadened owing to the energy transfer from Sm³⁺ to Eu ³⁺. This broadening makes the Ar⁺ 488 nm wavelength laser a powerful excitation source for Eu³⁺ fluorescence. The rare-earth doped glasses with various visible emissions are useful for developing new color light sources, fluorescent display devices, UV-sensor and tunable visible lasers.