Papers by Anne-Françoise Obaton
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ASM International eBooks, Jun 29, 2023
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Ce travail s'insere dans la recherche de nouveaux materiaux laser solides pompes par diode et... more Ce travail s'insere dans la recherche de nouveaux materiaux laser solides pompes par diode et emettant dans le domaine de securite oculaire localise autour de 1540 nm. La transition #4i#1#3#/#2#4i#1#5#/#2 de l'ion Er#3#+ est bien adaptee pour l'emission dans cette gamme spectrale. Cependant, son absorption dans le domaine d'emission des diodes laser est faible, aussi lui associe-t-on souvent l'ion Yb#3#+ dont la bande d'absorption se situe autour de 980 nm. Afin d'obtenir le materiau le plus performant, nous avons elabore differents verres codopes Yb#3#+Er#3#+ dont nous comparons les proprietes thermiques et spectroscopiques avec celles d'un verre industriel de reference (Kigre). Nous nous sommes interesses aux verres de phosphate Znoal#2o#3la#2o#3p#2o#5 (Zalp), Al#2o#3li#2op#2o#5 (Allip) et La#2o#3li#2oli#2p#2o#5 (Lalip#4o#1#2) et au verre de fluorophosphate Napo#3baf#2yf#3 (Nby). Nous presentons dans ce memoire les processus d'elaboration de ces verres ainsi que la determination de certaines de leurs proprietes physico-chimiques. En particulier, des mesures de conductivite thermique ont ete pratiquees car il s'avere que ce parametre est un des principaux problemes poses par les verres. Une etude spectroscopique est menee. Elle comprend l'absorption a partir du niveau fondamental des ions Yb#3#+ et Er#3#+ pour les calculs de Judd-Ofelt ainsi que l'emission et les declins de fluorescence. Nous nous sommes egalement penches sur les transferts entre l'ion Yb#3#+ et Er#3#+ et sur l'absorption entre les etats excites. Au terme de cette etude spectroscopique, des tests de gain et en cavite laser nous ont permis d'estimer les potentialites de certains de nos echantillons. Enfin, une etude par spectroscopies Raman et Brillouin nous a permis de sonder la microstructure de nos matrices vitreuses. Le verre Lalip#4o#1#2 codope Yb#3#+Er#3#+ s'est revele etre le plus adapte a la realisation de lasers a securite oculaire. Le rendement differentiel et le seuil laser de ce verre sont competitifs avec ceux du verre Kigre Qx.
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Proceedings of SPIE, May 5, 2011
A phase-sensitive optical low coherence interferometer is investigated experimentally to implemen... more A phase-sensitive optical low coherence interferometer is investigated experimentally to implement a new optical reference standard in the field of biology. This interrogation technique is associated to a planar cyclic resonant sensor such as an optical waveguide-based micro-cavity. The biological solution to be analyzed will be brought onto the surface of the sensor through a micro-fluidic cell. The aim of this association is to quantify low concentrations of analytes and to realize a real-time investigation of the kinetics of specific molecules with time and temperature for metrological applications, with better sensitivity and accuracy than existing techniques. This paper deals with the results of a feasibility study on the PS-OLCI technique as a new reference in the field of biology.
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ASM International eBooks, Jun 30, 2023
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Additive manufacturing, Apr 1, 2023
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Open ceramics, Sep 1, 2020
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Welding in The World, Jan 7, 2021
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HAL (Le Centre pour la Communication Scientifique Directe), Jul 10, 2012
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Concerning short distance fiber optic devices, down to less than one meter long, a phase-sensitiv... more Concerning short distance fiber optic devices, down to less than one meter long, a phase-sensitive optical low coherence reflectometer (OLCR) has been developed. This technique is well suited because it allows fast complex reflectivity measurements and overall working on short fiber lengths with a very good resolution.
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Welding in The World, Nov 29, 2022
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Metrologia, Jan 18, 2008
The optical low-coherence reflectometer (OLCR) is a very powerful tool to characterize optical fi... more The optical low-coherence reflectometer (OLCR) is a very powerful tool to characterize optical fibres and integrated optical components. However, this is a very complex set-up and in addition to that it performs Fourier transforms. Evaluating uncertainty in these conditions becomes very complicated. To overcome this difficulty, we chose to use an alternative statistical method as partly described in the ISO5725
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Metrologia, Mar 20, 2007
The measurement uncertainty of the spectral irradiance of an UV lamp is computed by using the law... more The measurement uncertainty of the spectral irradiance of an UV lamp is computed by using the law of propagation of uncertainty (LPU) as described in the 'Guide to the Expression of Uncertainty in Measurement' (GUM), considering only a first-order Taylor series approximation. Since the spectral irradiance model displays a non-linear feature and since an asymmetric probability density function (PDF) is
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Measurement Science and Technology
An x-ray computed tomography (XCT) interlaboratory comparison campaign, involving an aluminium-ma... more An x-ray computed tomography (XCT) interlaboratory comparison campaign, involving an aluminium-machined object, whose dimensions (92 × 78 × 63 mm3) are significant for a 225 kV XCT system, was performed for the purpose of investigating the performances of industrial XCT systems for dimensional measurements in terms of accuracy, i.e. precision and trueness, and to evaluate the influence of the measurement protocol (i.e. measurement strategy), of the operator and of the software on the results by comparison to reference measurements. In this campaign, we came to the conclusion that the measurement strategy is predominant, except for distance; that the measurement process is affected by the operator only for cylindricity and coaxiality; that there is no or little influence of the software except for coaxiality and position; and that a volumetric Gaussian filter allows to improve the measurements only for some participants’ measurements Furthermore, different behaviours, in terms of pre...
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The osseointegration process in and around additively manufactured (AM) lattice structures of a n... more The osseointegration process in and around additively manufactured (AM) lattice structures of a new titanium alloy, Ti–19Nb–14Zr, was evaluated. Three different implants, including lattices with increasing high sidewalls gradually closing them, were designed, manufactured and implanted in the tibia and metatarsal bone of two sheep for twelve weeks. After removal, they were characterized with X-ray computed tomography (XCT). The 3D XCT images were segmented using machine learning. The bone-interface implant (BII) and bone-implant contact (BIC) were studied. The results show that, since AM naturally leads to high roughness surface finish, the wettability of the implant is increased. The new alloy possesses an increased affinity to the bone enhancing the quality of osseointegration. The lattice provides crevices, in which the biological tissue can jump in and cling. The combination of these factors is pushing ossification beyond its natural limits. Therefore, the quality and speed of t...
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Les proprietes modales d'une fibre optique a large aire de mode, rendue effectivement unimoda... more Les proprietes modales d'une fibre optique a large aire de mode, rendue effectivement unimodale par discrimination de pertes des modes d'ordre superieur, ont ete caracterisees pour la premiere fois par la technique de reflectometrie optique en lumiere incoherente sensible a la phase. Les mesures ont ete faites suivant plusieurs parametres experimentaux, dont les conditions d'excitation des modes de la fibre et la longueur de celle-ci. Nous identifions plusieurs quasi-modes LP, et quantifions leur indice de groupe autour de 1,55 µm.
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AIP Advances, 2012
Herein, we highlight a behavior underlying the physics of Fabry-Pérot micro-cavities with distrib... more Herein, we highlight a behavior underlying the physics of Fabry-Pérot micro-cavities with distributed reflectors as there is a need to discriminate between effective and physical cavity lengths. Hence, Phase-Sensitive Optical Low Coherence Interferometry has been implemented to characterize micro-cavities with planar or curved reflectors. Beside the retrieved physical length, we obtain valuable information about the reflector thickness and number of layers. The accuracy of the technique has been estimated. Results suggest that this technique might be suitable to retrieve dimensional characteristics of any device constructed from multiple dielectric layers, whose thickness ranges from 2 micrometers up to hundreds of micrometers.
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Revue française de métrologie, 2011
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Sensors and Actuators A: Physical, 2013
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Papers by Anne-Françoise Obaton