RANGE OF CRYSTAL-FIELD STRENGTH IN VARIOUS FLUORIDE GLASSES

An important physical property of a rare-earth-doped glass is its loca l crystal field, because observed spectra, both in absorption and emis sion, are direct consequences of its strength and symmetry. However, b ecause of the inherent site inhomogeneity linked with the glass struct ure, 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 paramete r, N(nu), already defined for crystals. Using Nd3+ as a probe, a syste matic study of fluoride glasses of various compositions is presented. As an application of the use of N(nu) in the tailoring of some spectro scopical properties of fluoride glasses, prediction of the self-quench ing properties of Nd3+ (F-4(3/2)) is presented.