LASER-INDUCED POLARIZED FLUORESCENCE IN CUBIC YTTRIUM SESQUIOXIDE DOPED WITH TRIVALENT EUROPIUM

The fluorescence spectrum of Eu3+ in the C2ü approximately C2v site of the C-Y2O3 structure was recorded using a tunable dye laser to populate the D05 level of the 4f6 configuration. Because the active ion occupies an anisotropic point site in an overall cubic unit cell one can make use of the Feofilov theory to interpret the experimental polarization of the emission lines. The polarized laser beam was applied perpendicular to the (111) plane of a single crystal and the polarization for each line of the D05 F1,2,3,47 transitions was measured. From the data the irreducible representations associated with the Stark levels can be found. In particular the transitions A1 A1 and A1 A2 can be unambiguously distinguished from A1 B1 and A1 B2. A preliminary crystal-field analysis was undertaken on the basis of the 49 FJ7 states using an Hamiltonian (including spin-orbit coupling) written in true C2 symmetry, that is including imaginary crystal-field parameters. To derive approximate values of the crystal-field parameters the electrostatic point-charge model was applied. © 1979 The American Physical Society.