SELECTIVE LASER EXCITATION AND INHOMOGENEOUS BAND BROADENING OF ND3-YF3 CRYSTALS( IONS IN DISORDERED CAF2)

We have investigated the structure of inhomogeneously broadened absorp tion and fluorescence bands of Nd3+ ions in disordered yttrofluorite c rystals by selective laser excitation at T = 77 K. Measurements of the Stark splittings of I-4(9/2) multiplet for two groups of optical cent ers were obtained and indicate a linear change of Stark level energies for the two groups of centers as the excitation frequency was changed . The dispersion of the Stark splittings displays a weak correlation o f energies between the resonant transition and nonresonant ones for bo th center groups. Finally, an analysis of the spectra of nonresonant l aser excitation at several fluorescence lines for the two groups of ce nters has also allowed us to observe energy levels in the high lying ( 4)G(5/2), (2)G(7/2) multiplets.