Yb3+-Doped Titanate–Germanate Glasses for Near-IR Luminescence Applications: Synthesis, Characterization, and the Influence of TiO2 Concentration

In the framework of luminescent rare-earth-doped glasses for near-infrared applications, TiO₂-containing inorganic glasses have been recently demonstrated to be a promising alternative to commercially used high-phonon SiO₂-based glasses. This study investigates the effect of TiO₂ concentration on the near-infrared spectroscopic properties of Yb³⁺ ions in multicomponent titanate-germanate glasses. A series of glass samples in the xTiO₂-(60-x)GeO₂-BaO-Ga₂O₃-Yb₂O₃ system (x ranging from 0 to 50 mol%) were synthesized using the melt-quenching technique. X-ray diffraction analysis confirmed the fully amorphous nature of the fabricated titanate-germanate samples. Fundamental spectroscopic properties of Yb³⁺-doped titanate-germanate system consisting of absorption spectra, near-IR emission spectra, and luminescence decay curves have been determined based on measurement using optical spectroscopy. The intensity of the emission band at 1 µm due to the ²F_5/2 → ²F_7/2 laser transition of Yb³⁺ ions increases by over 2.3-fold (TiO₂ as the network former) compared to a barium gallo-germanate sample without TiO₂. Our previous studies indicate that Yb³⁺-doped titanate-germanate glass is a promising optical material and could be successfully applied to laser technology.