Composition dependent upconversion of Er3+-doped PbF2–TeO2 glasses

The upconversion properties of Er3+ ions were studied for heavy metal oxyfluoride tellurite glass hosts xPbF2–(100−x)TeO2 under 975 nm excitation. The intense green (529 and 545 nm) and relative weak red (657 nm) emissions corresponding to the transitions 4S3/2 → 4I15/2, 2H11/2 → 4I15/2 and 4F9/2 → 4I15/2, respectively, were simultaneously observed at room temperature. The PbF2 content has an important influence on upconversion luminescence emission. With increasing PbF2 content, the intensities of green (529 nm) and red (657 nm) emissions increase slightly, while the green (545 nm) emission increases significantly. These results indicate that PbF2 has more influence on the green (545 nm) emission than the green (529 nm) and red (657 nm) emissions. The intense green emission observed suggest that Er3+-doped heavy metal oxyfluoride tellurite glasses can become candidates for developing upconversion optical devices.