@article{6004,
  author = {J. P. R. Wells and H. C. Gallagher and T. P. J. Han},
  title = {Crystal-growth and spectroscopy of Er3+ ions in calcium gallogermanate},
  abstract = {This paper reports on the Czochralski growth of large single crystals of Er3+ doped Ca3Ga2Ge4O14 (CGGO) in radio frequency heated induction furnaces operating at 18 kHz. Crystals were successfully grown at concentrations of 0.005, 0.05, 0.5 and 5 mol% of the ErF3 dopant, and were of exceptionally good optical quality. Spectroscopic studies of the intra-4f shell absorption and fluorescence transitions of the Er3+ ions in this material were performed at 10 K, Measurements of the optical linewidths show no signs of concentration broadening up to 5 mol%, a feature attributable to the intrinsic compositional disorder of the crystal. We have identified 67 crystal-field levels of the C-2 symmetry site available for occupation by a trivalent rare-earth ion and observe strong up-conversion fluorescence for excitation (both resonant and non-resonant) of the absorption transitions from the ground state to the F-4(9/2) multiplet. Prominent self-absorption dips observed in excitation spectra recorded whilst monitoring up-converted fluorescence, demonstrate the importance of radiative energy transfer at high concentrations. (C) 2000 Elsevier Science B.V. All rights reserved.},
  year = {2000},
  journal = {Journal of Crystal Growth},
  volume = {217},
  number = {3},
  pages = {302-310},
  month = {Aug},
  isbn = {0022-0248},
  doi = {10.1016/s0022-0248(00)00485-1},
  language = {eng},
}