LASER SPECTROSCOPY OF Bi4Ge3O12 SINGLE CRYSTALS : EMISSION MECHANISM AND SATURATION EFFECTS F. Rogemond, C. Pedrini, B. Moine and G. Boulon J. Phys. Colloques, 46 C7 (1985) C7-459-C7-462 DOI: 10.1051/jphyscol:1985781