Praseodymium-doped alkali bismuth gallate glasses

We propose and demonstrate alkali bismuth gallate glasses as suitable hosts for the rare earth praseodymium (Pr³⁺) operating at 1.3-αm wavelength. The structure of the glasses was investigated by Raman spectroscopy. The optical absorption and the photoluminescence properties of Pr^3- in these glasses were characterized. The Raman spectrum shows two strong peaks, at 134 and 381 cm^-1, and a weak peak at 660 cm^-1. The results indicate that bismuth (Bi³⁺) and gallium (Ga³⁺) cations do take part in the formation of the glass network. The emission from the Pr³⁺: ¹G₄ → ³H₅ transition is at 1.34-μm wavelength, and the spectral bandwidth is 120 nm, which is wider than those of fluoride and chalcogenide glasses. The lifetime of the ¹G₄ level is ∼78 μs, and the quantum efficiency is ∼17.4%, which is higher than that in fluoride glasses.