Manifestation of Nd ions on the structure, Raman and IR spectra of (TeO2-MoO-Nd2O3) glasses

The structure of [80TeO2 + (20–x)MoO+xNd2O3] glasses, with x = 0, 4, 6, 10 and 12 mol%, is studied in this work. Raman scattering in the spectral range (−2000 to 3500 cm−1) and IR absorption spectra have been measured for crystalline TeO2 and glasses, and their assignments were discussed and compared. Many vibrational modes were found active in both Raman and IR and their assignments for crystalline TeO2 and for the glasses were discussed in relation to the tetragonal structure of crystalline α-TeO2. Nd2O3 was found to completely eliminate diffuse scattering and enhance the Raman scattering intensity. Anti-stokes Raman bands in the range −1460 cm−1 to −1975 cm−1 were observed for both (30Li2O + 70B2O3 + xNd2O3) glasses and [80TeO2 +(20 − x)MoO+xNd2O3] glasses and were attributed to some emission processes due to the doping of the glasses with Nd2O3. C 2005 Springer Science + Business Media, Inc. 1. Introduction Due to their stability, low crystallization rate, excellent transparency in a wide spectral region (3–18 μm) and many other significant properties, Tellurite glasses are important in many technological applications. As reported in the literature, TeO2 based glasses are considered as excellent materials for possible uses in nonlinear optical devices, host materials for upconversion fluorescence of rare earth ions and high speed laser communication systems [1, 2]. Such importance of Tellurite glasses is in principle due to their specifically high electron-phonon anharmonicity [3]. The structure of binary (TeO2-MoO) glasses and (TeO2-MoO) crystalline systems and some other TeO2-based glasses have been studied by XRD analysis, IR, Raman scattering and DSC [4–10], where bond lengths, way of bonding and the interactions among TeO4, TeO3+1, TeO3 and the glass modifier cations have been discussed. TeO2-based glasses are known as good hosts for rare earth ions (e.g. Nd2+, Er3+) in possible uses for practical laser applications [11]. Upconversion fluorescence was observed for the first time in Tellurite glasses of the composition (70TeO2·30Na2O·1Er2O3), and Er3+ ions were found to be relatively more important in Tellurite glasses than Nd2+ [12, 13]. Some important properties of Er3+ doped Tellurite glass fibers have been published and this work has attracted a strong attention because of its importance in increasing the transmission capacity of some high-speed communication systems [14, 15]. Upconversion fluorescence has been reported in ∗Author