New progresses in transparent rare-earth doped glass-ceramics

Recent advances in rare-earth doped transparent fluoride glass-ceramics with high crystallisation level (90%) are reported. The first stages of the devitrification process have been studied by X-ray scattering and their precursor signs observed by Raman spectroscopy. Transmission Electron Microscopy and X-ray microanalysis have also been used to measure the composition fluctuations inducing the spinodal decomposition responsible for the devitrification of this family of glasses. The optical spectroscopy of the erbium ion in the glass-ceramics shows crystal-like spectra, A reduction of inhomogeneous linewidth by a factor of 2 is observed between glass and glass-ceramic on different transitions resulting in an increase of the maximum cross-sections. The lifetime of the different measured levels is kept constant or increased by the ceramming process. (C) 2001 Elsevier Science B.V. All rights reserved.