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 absorpt ion and emission cross-sections were measured. The controlled crystallisati on of the fluoride compounds by nucleation and growth in the oxide matrix p roduced crystallites similar to 10 nm in size and a filling factor of 10(-2 ). The phase separation process was investigated using thermal and structur al analysis. Changes were observed in the optical properties of the glass a fter 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 absorpt ion cross-section, up to 100%, was obtained at room temperature. (C) 1999 E lsevier Science B.V. All rights reserved.