Influence of Sm₂O₃ ion concentration on physical and thermal properties, and Raman gain coefficient of TeO₂–Li₂O–ZnO vitreous system

In this paper, a vitreous matrix 65TeO₂–15Li₂O–20ZnO (TLZ) doped with different concentrations of Sm₂O₃ (0.1, 0.15, 0.2, 0.35, 0.5, and 1.0 mol%) was produced via melt-quenching technique. The influence of the concentration of Sm₂O₃ ions on physical and thermal properties, and the Raman gain coefficient of TLZ glass samples, has been investigated. From the X-ray diffractograms, it was obtained that adding Sm₂O₃ ions had no discernible effect on the overall properties of the TLZ glass samples, keeping the amorphous nature of the glass structure. In addition, it was observed that the density of the samples increased with the incorporation of the Sm³⁺ ions. Furthermore, the molar volume of the TLZ glass samples increased and the oxygen packing density (OPD) decreased, with the insertion of the Sm₂O₃. These results indicated that the Sm³⁺ ions are actively involved in the glass structure by forming bonds with the non-bridging oxygen (NBO) species. Another important result was the investigated sample thermal stability (ΔT) that remains constant up to a concentration of 0.15 mol% of Sm₂O₃ and then increases with the additional Sm₂O₃. In addition, the Raman analyses, for an excitation at 532 nm, revealed that the incorporation of Sm³⁺ ions does not significantly affect the Te–O–Te bonding environment. The refractive index of the samples was determined, and it was obtained that the refractive index increased with the incorporation of Sm³⁺ ions. Finally, the Raman gain coefficient was also investigated for the peaks centered at 988 and 2091 cm⁻¹, and it exhibited a minimum value at a Sm₂O₃ concentration of approximately 0.5 mol%. In conclusion, these results indicate that the TLZ glass samples are good candidates for high-speed optical communications due to their interesting properties and higher Raman cross-section compared to other glassy systems.