M S Sajna, Muhammad Zubair, G Vimal, N V Unnikrishnan
Er3+-doped zinc borotellurite glasses with the nominal composition (60 - x) TeO₂ + 30H₃BO₃ + 10ZnF₂ + xEr₂O₃ across a range of dopant concentrations were successfully prepared via the standard melt-quench route. The compositional, structural, and optical characteristics of these materials were thoroughly examined through energy-dispersive X-ray spectroscopy (EDS), Raman scattering spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, UV-Vis-NIR absorption, and photoluminescence investigations. XRD confirmed the glassy, non-crystalline character of the prepared glasses, and the functional vibrational groups of the Er3+-doped boro-tellurite glass were identified from Raman and FTIR analysis. The Intra-4f transition bands of Er3+ ions in the prepared glass were evaluated by UV-Vis-NIR absorption spectra and analysed in detail by JO theory. Furthermore, the high radiative lifetime of 3.5 ms and favorable branching ratio obtained for TBF50 glass indicate that the prepared glass matrix can be proposed as a promising candidate laser host material. The strong green and NIR emission of the glass is investigated in detail by photoluminescence analysis, and possible energy pathways were suggested. Based on the peak visible emission intensity observed across the series, TBF50 is identified as the most promising composition for visible green emission, while TBF75, showing the highest NIR emission intensity and a favorable linewidth and emission cross section, is identified as the most promising candidate for further development toward C-band fiber amplifier and infrared laser applications.