Rare-earth doped transparent glass-ceramics with high cross-sections

Erbium doped oxy-fluoride glass-ceramics (50GeO(2),[50-x]PbO,xPbF(2)) have been prepared by thermal treatments of as-melted glass. The optical absorption and emission cross-sections were measured. The controlled crystallisation of the fluoride compounds by nucleation and growth in the oxide matrix produced crystallites similar to 10 nm in size and a filling factor of 10(-2). The phase separation process was investigated using thermal and structural analysis. Changes were observed in the optical properties of the glass after reheating (10 h at 360 degrees C). The inhomogeneous linewidth of the I-4(15/2) <-> S-4(3/2) transition was reduced by 50% by incorporating most of the Er ions in the crystalline phase. An increase of the maximum absorption cross-section, up to 100%, was obtained at room temperature. (C) 1999 Elsevier Science B.V. All rights reserved.