Measurements of the absorption and emission spectra and the characteristics of the luminescent decay of the 4I11/2 and 4I13/2 energy levels of Er3+ are presented for Er3+ singly doped and Er3+, Pr3+-codoped PbO-Bi2O3-Ga2O3 (PBG) glasses. The absorption cross sections were determined after accurate measurement both of glass component concentrations by use of electron probe analysis and of glass density. The characteristics of the luminescent decays were determined after direct pumping of the 4I11/2 and 4I 13/2 energy levels of singly doped Er3+ PBG glass with a tunable pulsed optical parametric oscillator for calculation of the macroscopic rate parameters (WETU) for energy transfer upconversion (ETU) for these energy levels. The values for WETU relevant to the 4I11/2 energy level were measured to be greater than the WETU values relevant to the 4I13/2 energy level within the range of Er3+ concentrations studied. The macroscopic rate parameter (WEr-Pr) for energy transfer to the Pr3+ deactivator ion from the 4I13/2 energy level was also determined for a range of Pr3+ concentrations and for two fixed Er3+ concentrations. From a measurement of the energy-level lifetimes it was established that the rate of energy transfer from the 4I13/2 energy level to Pr3+ is greater than the corresponding rate of energy transfer from the 4I 11/2 level to both the Pr3+ ion and the OH impurity. The overall results suggest that, to maximize the population inversion on the 4I11/22→4I13/2∼3 μm transition, deactivation of the 4I13/2 level by way of small amounts of Pr3+ will be effective.
|Number of pages||11|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|Publication status||Published - 2002|