%0 Journal Article
%T Photodarkening of Infrared Irradiated Yb3+-Doped Alumino-Silicate Glasses: Effect on UV Absorption Bands and Fluorescence Spectra
%A Hrvoje Gebavi
%A Daniel Milanese
%A Stefano Taccheo
%A David Mechin
%A Achille Monteville
%A Francesca S. Freyria
%A Barbara Bonelli
%A Thierry Robin
%J Fibers
%D 2013
%I MDPI AG
%R 10.3390/fib1030101
%X The photodarkening phenomenon in alumino-silicate glass preforms, doped with different ytterbium concentrations, was studied. The UV band, comprised between 180 and 350 nm, was examined before and after irradiation at 976 nm. The non-linear dependence of 240 nm band with concentration after infra-red irradiation was demonstrated and ascribed predominantly to Yb 3+ pair¡¯s interaction. The emission spectrum after the excitation in UV spectral region showed increased intensity after photodarkening, probably due to Yb 2+ ions creation. Phenomenological photodarkening model and the possible existence of several defect types are presented.
%K photodarkening
%K Yb-doped fibers
%K high power lasers
%U http://www.mdpi.com/2079-6439/1/3/101