Optical absorption and self activated upconversion fluorescence spectra of Tm3+ ions in antimony borate glass systems

Optical absorption and fluorescence spectra of Tm3+ ions in Sb2O3–B2O3 glasses mixed with three different modifier oxides viz., PbO, CaO and ZnO have been recorded at room temperature. The radiative transition probabilities and branching ratios evaluated for various luminescent transitions suggested the highest value for G 4 1 → H 6 3 transition among various other transitions in all the three glass systems. The analysis of these data further suggested that the comparatively high non-radiative losses in ZnO mixed glasses. We have also demonstrated the upconversion from red to blue emission (from D 2 1 and G 4 1 emitting levels) in these glasses with two step absorption mechanism using F 4 3 and H 4 3 levels as intermediate levels.