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Seminar Announcement: Franck Mady

posted Nov 5, 2018, 8:13 AM by Stefano Varas   [ updated Nov 5, 2018, 8:13 AM ]

Announcement
Monday, 5 November 2018, 10:00
Sala Grande Palazzina C via alla Cascata 56/C

"Role of some rare-earth dopants (Yb, Er, Yb/Ce) in the mechanism of radiation-induced degradation of aluminosilicate-core optical fibers"

Franck Mady
Université Côte d’Azur, CNRS, INФNI, UMR7010,
Parc Valrose, 06108 Nice Cedex 2, France

Abstract
This talk proposes a systematic review of the defects created in silica, in aluminosilicate, and in Yb-, Er- and Yb,Ce-doped silicate or aluminosilicate glasses under ionizing irradiation. The mechanisms of radiation-induced attenuation (RIA) development and annealing, including that of the RIA mitigation by Ce, are also presented. The reduction of rare-earth ions is always observed under irradiation, by electron trapping, accompanied of course by the trapping of holes, preferably at Al-substituted thetrahedral sites. Annealing mechanisms involve the recombination of holes with reduced RE ions, with emission of the charge-transfer relaxation of Yb3+ ions (regardless of co-doping) or that of Er3+ ions. Ce4+ ions are not restored by recombination, but by electron release at moderate temperature (below 500 °C).

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Stefano Varas,
Nov 5, 2018, 8:13 AM