Solid state spectroscopy : the transverse zeeman effect in CaF₂:Erᶾ⁺ crystals
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
A detailed investigation has been made of the transverse Zeeman effect for erbium ions at tetragonal C₄ᵥ sites in CaF₂ crystals. Selective laser excitation of fluorescence from the transverse Zeeman site using a dye laser beam enabled this site to be distinguished from two other magnetically non-equivalent sites in these crystals. Large intensity and energy variations observed for some transverse Zeeman transitions as the crystal was rotated in the magnetic field, were accounted for by a switching of the symmetry labels and by magnetic field mixing between levels. The C₄ᵥ irrep designations of the crystal-field levels were identified by studying the intensity variations, and crystal and magnetic field energy calculations successfully accounted for the energies of the transverse Zeeman levels. In certain cases, the transverse Zeeman effect was analysed in the more complex absorption spectra. Previous undetected C₄ᵥ crystal-field energy levels in CaF₂:Erᶾ⁺ have been located using selective laser excitation spectroscopy, and a few assignments of levels to the C₄ᵥ site by earlier workers, were found to be incorrect. Conventional optical absorption and fluorescence measurements have been made on Ndᶾ⁺ ions in CaF₂ and SrF₂ crystals, and infrared and infrared-Zeeman absorption spectra examined for Ceᶾ⁺ and Ndᶾ⁺ions in both types of crystalline hosts. Crystal-field analyses have been carried out for most crystals studied.