Radiative and nonradiative properties of neodimium doped silicate and phosphate glasses

Abstract

Compositional dependence of radiative and nonradiative properties of Nd 3+ were investigated in silicate and phosphate glasses. Radiative decay rate is determined by the asymmetry and covalency of ligand field. The large radiative decay rate in phosphate glasses due to the large asymmetry connected with their chain structure. As the cationic field strength Z/a 2 of modifier increases, radiative decay rate increases in silicate glasses but decreases in phosphate glasses. This result indicates that in silicate glasses the distortion of ligand field increases with increasing Z/a 2, while in phosphate glasses the asymmetry increases with decreasing Z/a 2 because the configuration of the ligands becomes more deformable with decreasing Z/a 2 of cation connecting the chains. Nonradiative decay rate due to multiphonon relaxation is determined by the electron-phonon coupling strength and phonon energy. The nonradiative decay rate for the change of modifier cations are determined by electron-phonon coupling strength and those for the change of modifier contents are determined by phonon energy.