Optical study of GeO2–PbO–PbF2 oxyfluoride glass single doped with lanthanide ions

Glasses with composition 50GeO2–(50–x–y)PbO–yPbF2–xLnF3 (Ln = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+) were synthesised in the bulk form. The content of PbF2 was constant and amounted to 5 mol%, whereas the concentration of luminescent ions was 0.2 and 2 mol%. Absorption and emission spectra were investigated. The results were analysed in the framework of the Judd–Ofelt theory giving the values of the Ω2,4,6 intensity parameters, radiative probabilities Wr and radiative lifetimes τrad. The dynamics of luminescent levels was studied and experimental lifetimes were determined. Some generalisations with regards to radiative and non-radiative relaxations in GeO2–PbO–PbF2 doped with Ln3+ from Pr3+ to Yb3+ are carried out.