Judd-Ofelt intensity parameters and laser analysis of Pr3+ doped phosphate glasses sensitized by Mn2+ ions

In this paper, we report the preparation and optical characterization of Mn2+ activated Pr3+ doped phosphate glasses in four different chemical compositions. The optical absorption spectra of Pr3+ ions in phosphate glasses have been recorded in the UV-VIS-NIR region. From the data available in the optical absorption spectra, various spectroscopic parameters such as Slater-Condon (F-2 F-4, F-6), Racah (E-1, E-2, E-3), spin-orbit interaction (xi(4f)) and Judd-Ofelt (J-O) (Omega(2), Omega(4), Omega(6)) parameters are derived. The calculated values of the J-O parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (S-ed), magnetic dipole line strengths (Smd), radiative transition probabilities (A(RAD)), radiative lifetimes (tau(RAD)), fluorescence branching ratios (PR) and the integrated absorption cross-sections (sigma(a)) for stimulated emission from various excited states of Pr3+ ion. The principal fluorescence transitions of interest are identified by recording the fluorescence spectrum and measuring their stimulated emission cross-section and optical gain. Quantum efficiencies of the prominent lasing transitions are estimated by measuring their radiative and fluorescence lifetimes. The dependence of effective radiative lifetime on Pr3+ ion concentration is discussed in the light of non-radiative processes such as multiphonon relaxation and energy transfer between like and unlike ions. (C) 2000 Elsevier Science B.V. All rights reserved.