Spectroscopy of Pr 3+ ions in lithium borate and lithium fluoroborate glasses

Abstract

Optical absorption and emission spectra of 1 mol% Pr 3+ doped lithium borate and lithium fluoroborate glasses have been recorded. The intensities of f–f transitions are parameterized in terms of Judd–Ofelt (JO) intensity parameters Ω λ ( λ=2, 4 and 6). The JO parameters obtained with modified JO theory have been used to predict radiative properties such as spontaneous emission probabilities ( A), lifetimes ( τ R) and branching ratios ( β R) for all the 12 excited states of these Pr 3+ doped glasses along with some of the reported Pr 3+ : systems. The predicted β R are compared with the experimental values for the emission from 3P 0 and 3P 1 levels. The stimulated emission cross-sections are also evaluated for all the observed emission transitions. The β R values for the potential laser transitions including the 1G 4→ 3H 5 (1.3 μm) transition useful for fibre amplifier have been compared for 17 Pr 3+ : systems. The effect of compositional changes of the glasses on the optical properties of Pr 3+ ions have been discussed.