State-selective energy transfer from Er3+ to Eu3+ in Bi2O3-GeO2-Ga2O3-Na2O glasses

The Eu3+ ion was introduced into Er3+ doped Bi2O3-GeO2-Ga2O3-Na2O (BGGN) glasses to improve the 1.5 μm band emission. As a function of Eu2O3 doped content, we observed the increase in non-radiative decay rate of Er3+ not only 4I11/2 energy level but also 4I13/2 energy level, while the lifetime of Er3+:4I11/2 and 4I13/2 levels were shortened from 607 to 241 μs and from 3.37 to 1.88 ms, respectively. Accordingly, the upconversion fluorescence (green and red) was quenched. The total quantum efficiency of the Er3+:4I13/2 increased with the Eu2O3 content increasing up to 0.2 mol% due to the state-selective energy transfer from Er3+ to Eu3+.