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Synthesis, characterization and local changes induced by a cw argon laser in silica glass xerogel doped with transition metal ions

Abstract:

We report on the synthesis, characterization and local changes induced by a cw argon laser in SiO<inf>2</inf> xerogel doped with low metal ion concentrations, and obtained by the sol-gel process. The V, Mn and Cr metal ions were introduced into the SiO<inf>2</inf> matrix as inorganic salts and as an oxide in the case of Mo. The characterization of these materials showed that an amorphous system with high porosity was obtained; the metals were incorporated as ions with several different oxidation states, and the thermal diffusivity was around 10<sup>-9</sup> m<sup>2</sup>/s. In these xerogel monoliths it is possible to induce local changes in the refractive index with the incidence of a focused laser beam at 488 nm, about 80 μm in diameter, with power intensities from 1 to 48 mW and an incidence time from 0.5 to 5 min. After this process, a high contrast in the transmitted light between the processed area and the homogenous matrix is obtained, resulting in an optical memory effect. © 2006 Elsevier B.V. All rights reserved.