Luminescence Studies in Ca(PO₃)₂:Eu³⁺ Glass by Laser-Induced Fluorescence Line-Narrowing Technique. II. Distribution of the Crystal-Field Parameters

Abstract

The laser-induced fluorescence spectra of Eu³⁺ in Ca(PO₃)₂ glass are analyzed in detail. It is shown that the site-to-site variation of the energies of several levels of Eu³⁺ is expressed using the second-order crystal-field parameters B₂₀ and |B_2±2|. From the analysis of the spectral shape of the laser-induced fluorescence lines, the distributions of the above two parameters are determined. The fluorescence linewidth has been found to be very different for the lines to excite. This is explained by the difference in the dependence of the energies of the levels concerned on the crystal-field strength. The inhomogeneously broadened lineshape of the ⁵D₀−⁷F₀ fluorescence excited by the broad-band ultraviolet light is shown to be reproduced by assuming Gaussian distributions of the crystal-field parameters.