RANGE OF CRYSTAL-FIELD STRENGTH IN VARIOUS FLUORIDE GLASSES

An important physical property of a rare-earth-doped glass is its local crystal field, because observed spectra, both in absorption and emission, are direct consequences of its strength and symmetry. However, because of the inherent site inhomogeneity linked with the glass structure, usually very little can be said about the crystal field at a rare-earth site. In this paper, an extension to glasses, and particularly to fluoride glasses, is presented of the scalar crystal field parameter, N(nu), already defined for crystals. Using Nd3+ as a probe, a systematic study of fluoride glasses of various compositions is presented. As an application of the use of N(nu) in the tailoring of some spectroscopical properties of fluoride glasses, prediction of the self-quenching properties of Nd3+ (F-4(3/2)) is presented.