Optical intensities of holmium in tellurite, calibo, and phosphate glasses

The intensities of the electric dipole transitions of Ho³⁺ in three oxide glasses have been obtained from the absorption spectra in the visible and ir for tellurite glasses, and in the uv, visible, and ir parts of the spectrum for calibo and phosphate glasses. From the experimental values of the oscillator strengths and calculated matrix elements, the Judd-Ofelt intensity parameters were obtained by least-squares analysis. Radiative transition probabilities from the emitting (⁵S₂, ⁵F₄) and ⁵F₅ levels to all lower states were calculated using these parameters. Emission and excitation spectra and the decay times of the (⁵S₂, ⁵F ₄) fluorescence were measured. It was found that the fluorescence in tellurite glass has intensities two orders of magnitude higher than in the other two oxide glasses. A concentration dependence study of the fluorescence in tellurite glass was performed. A mechanism for the quenching is proposed.