Neodymium: Sodium beta double prime alumina as a laser medium

Sodium Beta Alumina is a solid ionic conductor in which trivalent rare-earths may be exchanged for sodium after a raw crystal is grown, in contrast to traditional laser hosts where the rare earth dopant is added to the basic crystal melt from the start. Samples of Sodium Beta Double Prime Alumina were exchanged with various concentrations of trivalent neodymium, absorption spectra have been taken for these samples, and a Judd/Ofelt analysis performed. Anomalously large values of oscillator strengths were observed for lines which depend strongly on a linear term in the crystal field. A point charge model with a simple modification for ligand dipole polarizability has been used to calculate Judd/Ofelt parameters for several possible deviations from near neighbor inversion symmetry. Parameters calculated for the types of distortions known to exist based on X-ray diffraction data agree moderately well with parameters calculated from spectra. The Judd/Ofelt parameters are used to calculated radiative lifetimes and stimulated emission cross sections, which are important data for potential laser candidates.