Enhanced thermal stability and optical properties in Tm3+/Dy3+ ions codoped TNbZ glasses

TNbZ host glasses within composition 90TeO2-10Nb2O5-10ZnO in mol% codoped with x(Tm2O3/Dy2O3), where x = 0, 10000, 20000 and 30000 ppm were prepared by using melt-quenching technique under dry oxygen streem. The thermal and optical properties of these glasses were estimated by using differential scanning calorimetric, DSC, and UV-vis-NIR spectroscopy respectively. The results of thermal analysis indicates that Tm3+/Dy3+ modified TNbZ host glass has high thermal stability and anticrystallization process. The density, oxygen packing density, molar volumes, oxygen molar volume, molar refraction, metallization criterion, molar polarizability, linear refractive index n, third-order non-linear susceptibility and two photon absorption coefficient were calculated. It was found that, the linear refractive index increases otherwise decrease in the optical energy gap with increase Tm3+/Dy3+ions. Raman scattering spectra and calculated Raman gain spectra of present glasses were studied. Addition of Tm3+/Dy3+ ions to TNbZ glasses increase in intensity due to distortion of [TeO4] units, Te-O-Te chains and [TeO3] units. The evaluated Raman gain coefficient of these glasses was found as 33-80 times that of fused-silica (0.89 × 10−13 m/W) at 440 cm−1. The results suggest that the present glass modified by Tm3+/Dy3+ may be promising candidate use in optical application like that Raman gain amplifier.