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Suppression mechanism of radiation-induced darkening by Ce doping in Al/Yb/Ce-doped silica glasses : evidence from optical spectroscopy, EPR and XPS analyses.
Autorzy
Rok wydania
2016
Czasopismo
Numer woluminu
120
Strony
153101/1-153101-8
DOI
10.1063/1.4964878
Kolekcja
Język
Angielski
Typ publikacji
Artykuł
Yb3+/Al3+ co-doped silica glasses with different Ce2O3 contents were prepared using the sol–gel method combined with high-temperature sintering. Changes in refractive index, absorption, emission and fluorescence lifetime of these glasses caused by X-ray irradiation were recorded and analyzed systematically. It is found that co-doping with certain amount of Ce could greatly improve the radiation resistance without evident negative effects on the basic optical properties of the Yb3+ ions in the near-infrared region. The nature of the radiation-induced color centres and the mechanism by which Ce prevented the formation of these centres were studied using optical absorption, electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) methods. Direct evidence confirmed that trapped electron centres (Yb2+/Si-E′/Al-E′) and trapped hole centres (Al-OHCs) were effectively inhibited by Ce doping, which was correlated to the coexistence of the redox couple Ce3+/Ce4+ in the glasses. These results are helpful to understand the micro-structural origin and the suppression mechanism by Ce co-doping of the photodarkening effect in Yb3+-doped silica fibers.
Adres publiczny
http://dx.doi.org/10.1063/1.4964878