Spectroscopic Properties of Inorganic Glasses Doped with Pr³⁺: A Comparative Study

The results presented in this communication concern visible and near-IR emission of Pr³⁺ ions in selected inorganic glasses, i.e., borate-based glass with Ga₂O₃ and BaO, lead-phosphate glass with Ga₂O₃, gallo-germanate glass modified by BaO/BaF₂, and multicomponent fluoride glass based on InF₃. Glasses present several emission bands at blue, reddish orange, and near-infrared spectral ranges, which correspond to 4f-4f electronic transitions of Pr³⁺. The profiles of emission bands and their relative intensity ratios depend strongly on glass-host. Visible emission of Pr³⁺ ions is tuned from red/orange for borate-based glass to nearly white light for multicomponent fluoride glass based on InF₃. The positions and spectral linewidths for near-infrared luminescence bands at the optical telecommunication window corresponding to the ¹G₄ → ³H₅, ¹D₂ → ¹G₄, and ³H₄ → ³F₃,³F₄ transitions of Pr³⁺ are dependent on glass-host matrices and excitation wavelengths. Low-phonon fluoride glasses based on InF₃ and gallo-germanate glasses with BaO/BaF₂ are excellent candidates for broadband near-infrared optical amplifiers. Spectroscopic properties of Pr³⁺-doped glasses are compared and discussed in relation to potential optical applications.