Micro-resonators based on integrated polymer technology for optical sensing

International audienceResearch on sensors has experienced a noticeable development over the last decades especially in label free optical biosensors. However, compact sensors without markers for rapid, reliable and inexpensive detection of various substances induces a significant research of new technological solutions. The context of this work is the development of a sensor based on easily integrated and inexpensive micro-resonator (MR) component in integrated optics, highly sensitive and selective mainly in the areas of health and food. In this work, we take advantage of our previous studies on filters based on micro-resonators (MR) to experiment a new couple of polymers in the objective to use MR as a sensing function. MRs have been fabricated by processing SU8 polymer as core and PMATRIFE polymer as cladding layer of the waveguide. The refractive index contrast reaches 0.16 @ 1550 nm. Sub-micronic ring waveguides gaps from 0.5 to 1 µm have been successfully achieved with UV (i-line) photolithography. This work confirms our forecasts, published earlier, about the resolution that can be achieved. First results show a good extinction coefficient of ~17 dB, a quality factor around 104 and a finesse of 12. These results are in concordance with the theoretical study and they allow us to validate our technology with this couple of polymers. Work is going on with others lower cladding materials that will be used to further increase refractive index contrast for sensing applications

Technologie d'optique intégrée au laboratoire Foton

National audienceCet article résume le panorama de l'état de l'art des technologies d'optique intégrée maitrisées au laboratoire Foton (Systèmes Photoniques) axé sur l'optique intégrée polymère active et passive, les guides en silicium et silice poreuse pour la réalisation de capteurs biologiques, ainsi que les applications des guides en verres spéciaux étudiés en collaboration avec d'autres laboratoires

Technologie d'optique intégrée polymère au laboratoire FOTON

National audienceCet article résume le panorama de l'état de l'art des technologies d'optique intégrée polymère maitrisées au laboratoire Foton (Systèmes Photoniques) et qui sont axées sur des circuits optiques actifs et passifs. Les objectifs sont orientés vers un fort confinement du mode de propagation, la génération d'effets non linéaires, l'hybridation avec d'autres matériaux et la réduction des pertes (couplage et propagation)

Freshwater Seepage Into Sediments of the Shelf, Shelf Edge, and Continental Slope of the Canadian Beaufort Sea

Long‐term warming of the continental shelf of the Canadian Beaufort Sea caused by the transgression associated with the last deglaciation may be causing decomposition of relict offshore subsea permafrost and gas hydrates. To evaluate this possibility, pore waters from 118 sediment cores up to 7.3‐m long were taken on the shelf and slope and analyzed for chloride concentrations and δ180 and δD composition. We observed downcore decreases in pore waters Cl− concentration in sediments from all sites from the inner shelf (<20‐m water depth), from the shelf edge, from the outer slope (down to 1,000‐m water depths), and from localized shelf features such as midshelf pingo‐like features and inner shelf pockmarks. In contrast, pore water freshening is absent from all investigated cores of the Mackenzie Trough. Downcore pore waters Cl− concentration decreases indicate regional widespread freshwater seepage. Extrapolations to zero Cl− of pore water Cl− versus δ180 regression lines indicate that freshwaters in these environments carry different isotope signatures and thus are sourced from different reservoirs. These isotopic signatures indicate that freshening of shelf sediments pore waters is a result of downward infiltration of Mackenzie River water, freshening of shelf edge sediments is due to relict submarine permafrost degradation or gas hydrate decomposition under the shelf, and freshening of slope sediments is consistent with regional groundwater flow and submarine groundwater discharge as far as 150 km from shore. These results confirm ongoing decomposition of offshore permafrost and suggest extensive current groundwater discharge far from the coast

Contribution à l'étude du comportement des planchers composites poutres - dalles alvéolées préfabriquées en béton

Les dalles alvéolées s'appuient généralement sur des voiles, des poutres en béton armé ou précontraint, voire métalliques. Ces poutres fléchissent, provoquant la déformation transversale des dalles alvéolées ainsi que des contraintes de cisaillement transversal. Ce mécanisme est à l'origine d'une diminution de la résistance à l'effort tranchant des dalles alvéolées pouvant aller jusqu'à 70 %. À l'opposé, lorsque les déformations de flexion transversale sont négligeables, les dalles alvéolées jouent le rôle de table de compression de la poutre, augmentant ainsi la résistance en flexion et à l'effort tranchant de la pièce. Il est donc essentiel de connaître le comportement des planchers composites poutres-dalles alvéolées pour utiliser des méthodes de dimensionnement adaptées à leur fonctionnement et simples à mettre en œuvre. Une approche couplée modélisation numérique-expérimentation a été choisie. La première partie est consacrée à l'étude numérique qui a permis de mettre en évidence la diminution de la résistance à l'effort tranchant suivant la rigidité de flexion du support. La deuxième partie rapporte les résultats de deux essais à échelle 1 différant par la rigidité de flexion de la poutre support. Ces essais ont permis de valider le modèle numérique et de construire un modèle analytique simpleHollow core slabs are generally supported by walls reinforced or prestressed concrete beams or metallic beams. Depending of the bending rigidity and forces applied on the floor, beams bending inducing a transversal deformation of hollow core slabs, so leading to transversal shear stresses. This mechanism is the cause of the reduction of shear strength of hollow core slabs, being able to go up to 70%. Contrary to, when hollow core slabs are supported on rigid supports, the hollow core slabs behave as a compression flange of the beam, thus increasing the bending and shear resistance of the composite T beam. It is essential to know the real behaviour of composites floors in order to elaborate simple and reliable design methods easy to apply. For that a coupled approach numerical simulation and experimentation has been chosen. The first part is dedicated to the numerical study of composites floors' behaviour. We could thus define the experimental tests and highlight the decrease of the shear strength according to the flexural stiffness of the support. The second part deals with the experimental study of the composites floors' behaviour. Two full scale tests have been carried out. The flexural stiffness of the support is the only difference. Those tests first allow validating the numerical results and second to highlight the decrease of the hollow core slabs' shear strengthINIST-CNRS (INIST), under shelf-number: RP 17272 / SudocSudocFranceF

CONTRIBUTION A L'ETUDE DES POTENTIALITES DU BETON ARME DE HAUTES PERFORMANCES PAR SIMULATION NUMERIQUE A L'AIDE DES ELEMENTS FINIS

TOULOUSE-INSA (315552106) / SudocSudocFranceF