Characterization of Tm3+ doped TNZL glass laser material

In this paper, a new tellurite glass (85TeO2·5.0Nb2O5·5.0ZnO·5.0LiF) doped with 1 mol% Tm2O3 was prepared by melt-quenching technique. Differential scanning calorimetry (DSC) measurements indicate a good thermal stability, X-ray diffraction patterns show no sign of crystallization. Precise refractive index measurements were performed on five different wavelengths by a prism spectrometer. The optical energy gap, the Sellmeier energy gap and the dispersion energy were estimated. Judd-Ofelt intensity parameters were evaluated in order to obtain electric and magnetic-dipole transition probabilities, branching ratios and radiative lifetimes of several excited states of Tm3+. The classical McCumber theory was used to evaluate the emission cross-sections for the 3F4→3H6 transition at a wavelength of around 1.8 µm. The characteristics of down-conversion luminescence in the visible range were studied by exciting Tm3+ ions into the 1G4 level. Furthermore the structure of this glass was analyzed by Raman spectroscopy.