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), 70PbO . 30CdO, and 70PbO . 30TeO(2) doped with Pr3+ Nd3+, and Eu3+ ions have been investigated. The transition energies of the absorption spectra of Pr3+ and Nd3+ ions are analyzed for the Racah parameters, configuration interaction terms, and spin-orbit coupling. The absorption spectral intensities of pr(3+) and Nd3+ ions are analyzed for the Judd-Ofelt parameters. The Judd-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 order 70PbO . 30TiO(2) > 70PbO . 30CdO > 70PbO . 30TeO(2). This trend has been correlated to that of oxide ion polarizabilities, which follow the same order. The radiative parameters, viz., transition probability (A), branching ratios (beta(R)), and stimulated emission cross sections (sigma(p)), for laser transitions have been obtained, The high Omega(2) for Pr3+ leads to significantly larger a, for the P-3(0) --> F-3(2) transition in these glass matrices compared to those in fluoride and oxyfluoride glasses. The room-temperature emission D-1(2) --> H-3(4) transition of Pr3+ is much larger in 70PbO . 30TiO(2) than in the other two glass systems. The emission spectra of Pr3+ show temperature effects due to the Boltzmann population. The red-to-orange intensity ratios in the emission spectra of Eu3+ also support strong covalency of the Ln-O bond. The phonon side-band spectra (PSB) of Eu3+ are correlated with the infrared spectra, The electron-phonon coupling strengths and phonon energies have been obtained in all the cases.