• glass-ceramics;
  • photoluminescence;
  • rare earths


In the present work, sodium niobium tellurite (SNT) glass-ceramics co-doped with Er2O3 and Yb2O3 were prepared and analyzed. Initially SNT glasses were prepared using high pure chemicals namely TeO2, Nb2O5, Na2CO3, B2O3, and SiO2. DTA analysis was performed to identify the glass transition (Tg) and crystallization (Tc) temperatures. Following the data of DTA, the initial host glass was annealed at different temperatures (450, 550, and 650 °C). From the XRD pattern, glass annealed at 650 °C is taken to be optimized temperature for the formation of glass-ceramics from the host glass. The glass-ceramics thus formed were found to be translucent rather transparent. Similar procedure is followed to form Er3+ single doped and Er3+, Yb3+ co-doped SNT glass-ceramics. It was found that the crystallite size in the glass-ceramics calculated from the Debye Scherrer's formula is around the nano scale. Optical absorption and Judd–Ofelt (J–O) calculations were done for the transparent glasses doped with the rare earths. Radiative properties were also estimated from the J–O parameters. NIR emission spectra specifically observing the 1.5 µm luminescence of Er3+ ion in the doped glasses and glass-ceramics were recorded. It was found that nano glass-ceramics co-doped with Er3+ and Yb3+ ions were of maximum efficiency compared to single Er3+ doped SNT glass which could be used for fiber amplifiers in the NIR region.