Optical spectroscopy of Eu3+ ions in lithium borate and lithium fluoroborate glasses

Optical absorption, excitation and emission spectra of Eu3+ ions in lithium berate and lithium fluoroborate glasses have been investigated. Judd-Ofelt intensity parameters are derived from the integrated absorption spectra an d also from the emission spectra under various constraints. The relative me rits of thermal correction to the oscillator strengths of the transitions o riginating from the ground state (F-7(0)) Of Eu3+ ion observed in the absor ption spectra have been discussed. The Judd-Ofelt parameters obtained from the emission spectra have been used to calculate the total spontaneous emis sion probabilities (A), lifetimes (tau(R)) and branching ratios (beta(R)) f or eight excited levels that include, K-5(6), P-3(0), H-5(3), L-5(7), D-5(3 ), D-5(2), D-5(1) and D-5(0). The predicted values of tau(R) and beta(R) ar e compared with the measured values for D-5(0) level. The stimulated emissi on cross-sections (sigma (lambda(p))) are also evaluated for the D-5(0) --> F-7(J) and D-5(1) --> F-7(J) transitions. The variation of optical propert ies with compositional changes of lithium oxide and lithium fluoride conten ts in the glasses are discussed and compared with similar results. (C) 2000 Elsevier Science B.V. All rights reserved.