Absorption and emission spectral properties of Pr3+, Nd3+, and Eu3+ ions in heavy-metal oxide classes

The optical properties of the heavy-metal oxide glasses 70PbO . 30TiO(2), 7 0PbO . 30CdO, and 70PbO . 30TeO(2) doped with Pr3+ Nd3+, and Eu3+ ions have been investigated. The transition energies of the absorption spectra of Pr 3+ and Nd3+ ions are analyzed for the Racah parameters, configuration inter action terms, and spin-orbit coupling. The absorption spectral intensities of pr(3+) and Nd3+ ions are analyzed for the Judd-Ofelt parameters. The Jud d-Ofelt parameter, Omega(2), suggests strong covalency for the Ln-O bond in these oxide glass matrices for both Pr3+ and Nd3+ ions and follow the orde r 70PbO . 30TiO(2) > 70PbO . 30CdO > 70PbO . 30TeO(2). This trend has been correlated to that of oxide ion polarizabilities, which follow the same ord er. The radiative parameters, viz., transition probability (A), branching r atios (beta(R)), and stimulated emission cross sections (sigma(p)), for las er transitions have been obtained, The high Omega(2) for Pr3+ leads to sign ificantly larger a, for the P-3(0) --> F-3(2) transition in these glass mat rices compared to those in fluoride and oxyfluoride glasses. The room-tempe rature emission D-1(2) --> H-3(4) transition of Pr3+ is much larger in 70Pb O . 30TiO(2) than in the other two glass systems. The emission spectra of P r3+ show temperature effects due to the Boltzmann population. The red-to-or ange intensity ratios in the emission spectra of Eu3+ also support strong c ovalency of the Ln-O bond. The phonon side-band spectra (PSB) of Eu3+ are c orrelated with the infrared spectra, The electron-phonon coupling strengths and phonon energies have been obtained in all the cases.