An investigation on the dependence of photoluminescence in Bi2O3-doped GeO2 glasses on controlled atmospheres during melting

We have investigated the influence of a range of melting atmospheres on the control of the photo-active Bi-ion states in a Bi2O3-doped germanate glass, having a molar composition of 70GeO2–18Li2O–11Ga2O3–1Bi2O3. The atmosphere during melting was controlled by purging with pure oxygen, air, and nitrogen. The melting temperatures investigated were in the range of 1200 to 1450 °C. The UV–visible absorbance and the photoluminescence (PL) spectroscopic characterizations in the visible (600–800 nm) and near-IR (1000–1500 nm) regions were carried out for determining the contributions of potential Bi-ion states on the absorbance and PL. The PL properties of undoped GeO2 glass were also compared for the analysis of potential defects states present in the structure.