1. Gamma and x-ray irradiation effects on different Ge and Ge/F doped optical fibersAziz Boukenter, N. Richard, Marco Cannas, Claude Marcandella, Layla Martin-Samos, Simonpietro Agnello, Diego Di Francesca, Mattia Fanetti, Imene Reghioua, Sylvain Girard, Antonino Alessi, Youcef Ouerdane, 2015, original scientific article Found in: ključnih besedah Keywords: optical fibers, Germanium, doping, cathodoluminescence, irradiation effect Published: 11.04.2016; Views: 4859; Downloads: 0
Fulltext (1,35 MB) |
2. Neutron irradiation effects on the structural properties of KU1, KS-4V and I301 silica glassesYoucef Ouerdane, A. Boukenter, A. Ibarra, Layla Martin-Samos, P. Martín, Nicolas Richard, Sylvain Girard, Luigi Giacomazzi, M. León, 2014, original scientific article Found in: ključnih besedah Summary of found: ...silica, defects, optical fibers, hardening... Keywords: silica, defects, optical fibers, hardening Published: 03.10.2018; Views: 3073; Downloads: 0
Fulltext (724,27 KB) |
3. Coupled theoretical and experimental studies for the radiation hardening of silica-based optical fibersR. Boscaino, M. Cannas, Youcef Ouerdane, A. Boukenter, S. Agnello, P. Paillet, Antonino Alessi, C. Marcandella, Diego Di Francesca, Layla Martin-Samos, Luigi Giacomazzi, Sylvain Girard, Nicolas Richard, 2014, original scientific article Found in: ključnih besedah Keywords: silica, defects, optical fibers, hardening Published: 03.10.2018; Views: 3039; Downloads: 0
Fulltext (803,09 KB) |
4. Radiation Effects on Optical Fibers and Fiber-Based SensorsNicolas Richard, Philippe Paillet, Youcef Ouerdane, A. Boukenter, Sylvain Girard, Layla Martin-Samos, Luigi Giacomazzi, Claude Marcandella, 2015, independent scientific component part or a chapter in a monograph Found in: ključnih besedah Keywords: Optical Fibers, radiation-induced point defects, dosimetry, ab-initio Published: 24.10.2018; Views: 2944; Downloads: 0
Fulltext (632,99 KB) |
5. OXYGEN-EXCESS RELATED DEFECTS IN SiO2-BASED MATERIALS: COUPLING THEORY AND EXPERIMENTSBlaž Winkler, 2019, doctoral dissertation Abstract: This work is primarily focused on application of standard first-principle computational approaches to model oxygen excess related point defects in amorphous silica. Atomic models with their respective electronic and optical properties are explored together with some conversion mechanisms between defect models.
The first chapter overviews extensive literature about the already known properties of oxygen related defects. Second chapter briefly introduces main methods that have been used in this research, in particular Density Functional Theory (DFT) as energy and force engine with short description of minimal energy path (MEP) algorithm used for modeling chemical/migration reactions, GW approximation for charged electronic excitations (band structure) and Bethe-Salpeter Equation (BSE) for neutral excitations (optical absorption and excitonic structure including electron hole interaction). The third chapter is devoted to the presentation of results. Thanks to the calculation of optical properties of peroxy bridge (POL), a correlation has been found between structural disorder, specifically dihedral angle dispersion, and low coupling with light, which has been identified as main reason why no clear absorption bands have been assigned to the POL. Structure and stability of some other defects, like interstitial ozone molecule (ozonyl) and dioxasilirane (silicon analogy of dioxirane), have been studied. These defects are usually not considered as most important species, however their calculated formation energies are lower compared to some known defects, which indicates they might be present in silica.
From a detailed study on possible reaction mechanisms, it has been found that ozonyl might be one of the most important intermediate steps for oxygen exchange reactions. Results also show that dioxasilirane can be spontaneously created during the interaction of oxygen with lone pair defects. By exploring different reactions between oxygen and pre-existing oxygen deficiency centers (ODCs), calculations predict two kinds of passivation behaviors: single-barrier reversible mechanisms with the formation of dioxasilirane-like groups, for which the network keeps the memory of the precursory lone pair defects, and single or multiple-barrier mechanisms, for which the network loses its memory, either because of the high reverse barrier or because of a reconstruction.
Final part of this research has been devoted to experimental characterization of the response and tolerance of optical fibers loaded with oxygen under irradiation. These include experiments on commercial fiber along with canonical samples (Optical fibers developed with the intention of studying correlations between different fabrication parameters, dopant/impurity concentration and doping concentrations). Studied fibers also include rare-earth doped fibers. Found in: ključnih besedah Summary of found: ...Atomic models with their respective electronic and optical properties are explored together with some conversion... ...of the response and tolerance of optical fibers loaded with oxygen under irradiation. These include... Keywords: Silica, DFT, GW-approximation, Bethe-Salpeter equation, NEB, defect, oxygen, oxygen excess centers, oxygen deficiency centers, optical absorption, optical fibers, radiation induced attenuation. Published: 07.05.2019; Views: 3257; Downloads: 182
Fulltext (13,18 MB) |
6. Overview of radiation induced point defects in silica-based optical fibersBlaz Winkler, Imène Reghioua, Simonpietro Agnello, Marco Cannas, Philippe Paillet, Nicolas Richard, Adriana Morana, A. Boukenter, Youcef Ouerdane, Vincenzo De Michele, Antonino Alessi, Sylvain Girard, Layla Martin-Samos, Luigi Giacomazzi, Diego Di Francesca, Thierry Robin, 2019, review article Found in: ključnih besedah Keywords: optical fibers, point defects, radiation-induced attenuation, GLPC, NBOHC, STH, ODC, P-doping, Ge-doping, Al-doping Published: 09.05.2019; Views: 2643; Downloads: 0
Fulltext (2,27 MB) |
7. v-P2O5 micro-clustering in P-doped silica studied by a first-principles Raman investigationNicolas Richard, Matjaž Valant, Sylvain Girard, Youcef Ouerdane, A. Boukenter, Antonino Alessi, Layla Martin-Samos, Luigi Giacomazzi, Stefano de Gironcoli, 2019, original scientific article Found in: ključnih besedah Summary of found: ...silica, POHC, optical fibers, Raman, EPR... Keywords: silica, POHC, optical fibers, Raman, EPR Published: 10.05.2019; Views: 2653; Downloads: 0
Fulltext (1,94 MB) |