PROBE IONS FOR LOCAL-STRUCTURE INVESTIGATIONS OF GLASSES

The successful design of materials for optic and laser technology need s tools of investigation. Besides physical, chemical and optical prope rties especially the spectroscopic behavior of these materials is impo rtant. Knowledge about the local structure of doped active ions may pr ovide the basis for tailoring of spectroscopic properties. Special ion s, e.g. Nd3+, Gd3+ or Pb2+ as so-called probe ions have been incorpora ted into optical glasses to probe relevant sites of the amorphous netw ork. The Nd3+: I-4(9/2)-->P-2(1/2) absorption transition has been used to sense the strength of the crystal field in the vicinity of the las er ion and to derive informations about emission properties of embeded laser ions. The Gd3+: P-6(7/2)-->S-8(7/2) emission transition at 315 nm is useful for determination of electron-phonon interactions. The Pb 2+ ion (S-1(0)-->P-3(0) absorption transition) has been applied as pro be ion for alkaline earth ion sites. The optical basicity of fluoride phosphate glasses with different phosphate content has been estimated. The application of probe ions for local structure investigations can give assistance in the complex process of material design. However, th ese methods should not be overestimated because of the huge numbers of parameters affecting the performance of a laser material and compleme ntary investigation methods must be used.