Spectroscopic properties of Pr3+ ions in lead germanate glass

The visible luminescence of Pr3+-doped lead germanate glass of composition (in mol%) 60PbO-40GeO(2) has been investigated for two pr(3+) concentrations at different temperatures by using steady-state and time-resolved laser spectroscopy. Concentration quenching of the D-1(2) emission is observed for pr(3+) concentrations higher than x = 0.05 mol% even at 4.2 K and attributed to a cross relaxation process. Anti-Stokes emission from the P-3(0) level following excitation of the D-1(2) state has been observed for the sample doped with 0.5 mol% of Pr3+. The temporal behaviour of the anti-Stokes emission from the P-3(0) level following excitation of the D-1(2) State suggests that energy transfer is responsible for the upconversion process.