20 research outputs found
Arbitrary Form Plasmonic Structures: Optical Realization, Numerical Analysis and Demonstration Applications
Surface plasmon resonance has attracted more and more attention thanks to its wide range of applications in numerous fields (physics, chemistry, biology, etc.). In this chapter, we present different aspects, from theoretical calculation and experimental fabrication to applications demonstration, related to arbitrary shape plasmonic nanostructures. First, numerical calculations based on finite-difference time-domain method were realized to investigate the plasmonic properties of gold nanostructures having various size and shapes. Then the direct laser writing method was demonstrated as an excellent tool for fabrication on demand of arbitrary nanostructures. Plasmonic structures were obtained indirectly by a standard lift-off method from a polymeric template and directly by tightly focusing a continuous-wave laser beam onto a metallic thin film. Finally, demonstration of various applications of fabricated plasmonic structures, namely plasmonic-based data storage, color nanoprinter, tunable filters, and plasmonic-magneto-optics sensors will be shown
Metamaterials for the infrared and applications
Les mĂ©tamatĂ©riaux sont des composites artificiels prĂ©sentant des propriĂ©tĂ©s Ă©lectromagnĂ©tiques quâon ne trouve pas dans la nature. MalgrĂ© des dĂ©veloppements spectaculaires durant la derniĂšre dĂ©cennie, le potentiel de ces structures aux longueurs dâondes optique nâest pas encore clairement dĂ©fini en raison de problĂšmes technologiques et de contraintes physiques telles que les pertes dans les mĂ©taux entrant dans la composition des mĂ©tamatĂ©riaux. Dans notre thĂšse, nous montrons que les mĂ©tamatĂ©riaux ont des propriĂ©tĂ©s trĂšs favorables dans le contexte de lâoptique intĂ©grĂ©e dans le proche infrarouge. Nous avons dĂ©veloppĂ© une stratĂ©gie pour incorporer des mĂ©tamatĂ©riaux dans des circuits photoniques qui nâabsorbent que trĂšs peu dâĂ©nergie. Pour cela, nous ne faisons pas directement agir lâensemble du mode guidĂ© avec les mĂ©tamatĂ©riaux, mais seulement une composante Ă©vanescente Ă lâextĂ©rieur du guide. Pour rĂ©aliser un tel adaptateur ou dâautres fonctionnalitĂ©s, il importe de dĂ©terminer quelle gĂ©omĂ©trie de mĂ©tamatĂ©riaux est la plus favorable aux applications infrarouges. Nous proposons dâutiliser des structures Ă base de fils dâor empilĂ©s couche sur couche. A lâaide de simulations numĂ©riques et dâexpĂ©riences en espace libre, nous montrons quâil est possible dâobtenir toute une gamme de rĂ©ponses optiques en contrĂŽlant le couplage entre les diffĂ©rents niveaux de fils, c'est-Ă -dire en ajustant la distance entre les fils ainsi que leur alignement. En particulier, nous avons rĂ©ussi Ă contrĂŽler sĂ©parĂ©ment la rĂ©ponse Ă©lectrique et magnĂ©tique de nos structures, ce qui offre une flexibilitĂ© de conception qui ne se rencontre pas dans les mĂ©tamatĂ©riaux proposĂ©s jusquâĂ prĂ©sent.Metamaterials are artificial composites with electromagnetic properties not found in nature. Although the development of metamaterials has experienced a tremendous growth over the past few years, their potential at optical wavelengths is not clearly established due to technological and physical constraints such as high material losses in this spectral range. Here we show that metamaterials have a great potential in the context of integrated optics in the near infrared. We developed a strategy to incorporate metamaterials in photonic circuits with minimal absorption losses. Our approach relies on making the guided modes interact with the metamaterials only through the evanescent tail outside the waveguide. To achieve such an adaptor and other functionalities, it is important to know what is the best geometry for near-infrared applications. We propose to use metamaterials based on multi-layers of Au cut wires. With numerical simulations and experiments, we show that it is possible to create a wide range of optical properties by controlling the interaction between the wires, i.e. by adjusting the distance between the wires and their alignment. In particular we were able to demonstrat
MĂ©tamatĂ©riaux pour lâinfrarouge et applications
Metamaterials are artificial composites with electromagnetic properties not found in nature. Although the development of metamaterials has experienced a tremendous growth over the past few years, their potential at optical wavelengths is not clearly established due to technological and physical constraints such as high material losses in this spectral range. Here we show that metamaterials have a great potential in the context of integrated optics in the near infrared. We developed a strategy to incorporate metamaterials in photonic circuits with minimal absorption losses. Our approach relies on making the guided modes interact with the metamaterials only through the evanescent tail outside the waveguide. To achieve such an adaptor and other functionalities, it is important to know what is the best geometry for near-infrared applications. We propose to use metamaterials based on multi-layers of Au cut wires. With numerical simulations and experiments, we show that it is possible to create a wide range of optical properties by controlling the interaction between the wires, i.e. by adjusting the distance between the wires and their alignment. In particular we were able to demonstrateLes mĂ©tamatĂ©riaux sont des composites artificiels prĂ©sentant des propriĂ©tĂ©s Ă©lectromagnĂ©tiques quâon ne trouve pas dans la nature. MalgrĂ© des dĂ©veloppements spectaculaires durant la derniĂšre dĂ©cennie, le potentiel de ces structures aux longueurs dâondes optique nâest pas encore clairement dĂ©fini en raison de problĂšmes technologiques et de contraintes physiques telles que les pertes dans les mĂ©taux entrant dans la composition des mĂ©tamatĂ©riaux. Dans notre thĂšse, nous montrons que les mĂ©tamatĂ©riaux ont des propriĂ©tĂ©s trĂšs favorables dans le contexte de lâoptique intĂ©grĂ©e dans le proche infrarouge. Nous avons dĂ©veloppĂ© une stratĂ©gie pour incorporer des mĂ©tamatĂ©riaux dans des circuits photoniques qui nâabsorbent que trĂšs peu dâĂ©nergie. Pour cela, nous ne faisons pas directement agir lâensemble du mode guidĂ© avec les mĂ©tamatĂ©riaux, mais seulement une composante Ă©vanescente Ă lâextĂ©rieur du guide. Pour rĂ©aliser un tel adaptateur ou dâautres fonctionnalitĂ©s, il importe de dĂ©terminer quelle gĂ©omĂ©trie de mĂ©tamatĂ©riaux est la plus favorable aux applications infrarouges. Nous proposons dâutiliser des structures Ă base de fils dâor empilĂ©s couche sur couche. A lâaide de simulations numĂ©riques et dâexpĂ©riences en espace libre, nous montrons quâil est possible dâobtenir toute une gamme de rĂ©ponses optiques en contrĂŽlant le couplage entre les diffĂ©rents niveaux de fils, c'est-Ă -dire en ajustant la distance entre les fils ainsi que leur alignement. En particulier, nous avons rĂ©ussi Ă contrĂŽler sĂ©parĂ©ment la rĂ©ponse Ă©lectrique et magnĂ©tique de nos structures, ce qui offre une flexibilitĂ© de conception qui ne se rencontre pas dans les mĂ©tamatĂ©riaux proposĂ©s jusquâĂ prĂ©sent
Métamatériaux pour l'infrarouge et applications
Les métamatériaux sont des composites artificiels présentant des propriétés électromagnétiques qu on ne trouve pas dans la nature. Malgré des développements spectaculaires durant la derniÚre décennie, le potentiel de ces structures aux longueurs d ondes optique n est pas encore clairement défini en raison de problÚmes technologiques et de contraintes physiques telles que les pertes dans les métaux entrant dans la composition des métamatériaux. Dans notre thÚse, nous montrons que les métamatériaux ont des propriétés trÚs favorables dans le contexte de l optique intégrée dans le proche infrarouge. Nous avons développé une stratégie pour incorporer des métamatériaux dans des circuits photoniques qui n absorbent que trÚs peu d énergie. Pour cela, nous ne faisons pas directement agir l ensemble du mode guidé avec les métamatériaux, mais seulement une composante évanescente à l extérieur du guide. Pour réaliser un tel adaptateur ou d autres fonctionnalités, il importe de déterminer quelle géométrie de métamatériaux est la plus favorable aux applications infrarouges. Nous proposons d utiliser des structures à base de fils d or empilés couche sur couche. A l aide de simulations numériques et d expériences en espace libre, nous montrons qu il est possible d obtenir toute une gamme de réponses optiques en contrÎlant le couplage entre les différents niveaux de fils, c'est-à -dire en ajustant la distance entre les fils ainsi que leur alignement. En particulier, nous avons réussi à contrÎler séparément la réponse électrique et magnétique de nos structures, ce qui offre une flexibilité de conception qui ne se rencontre pas dans les métamatériaux proposés jusqu à présent.Metamaterials are artificial composites with electromagnetic properties not found in nature. Although the development of metamaterials has experienced a tremendous growth over the past few years, their potential at optical wavelengths is not clearly established due to technological and physical constraints such as high material losses in this spectral range. Here we show that metamaterials have a great potential in the context of integrated optics in the near infrared. We developed a strategy to incorporate metamaterials in photonic circuits with minimal absorption losses. Our approach relies on making the guided modes interact with the metamaterials only through the evanescent tail outside the waveguide. To achieve such an adaptor and other functionalities, it is important to know what is the best geometry for near-infrared applications. We propose to use metamaterials based on multi-layers of Au cut wires. With numerical simulations and experiments, we show that it is possible to create a wide range of optical properties by controlling the interaction between the wires, i.e. by adjusting the distance between the wires and their alignment. In particular we were able to demonstratePARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF
Self-organisation of human hepatocytes into hepatic cords on a radially perfused microfluidic device
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Fluorescent Molecular Probe based optical fiber sensor dedicated to pH measurement of concrete
International audienceAn optical fiber sensor based on a fluorescent molecular probe has been developed to measure the pH of cementitious materials, from the early stages of the material hydration. A fluorescent molecular probe, Naphth-AlkyneOMe is en-trapped in a cross-linked polyvinyl alcohol-glutaraldehyde matrix to synthesize thin films with pKa values increasing with glutaraldehyde ratio. The obtained sensing films with an average thickness of 150”m show reversible responses to pH change. The developed optode has the required characteristics for the study of concrete, with a response time of 100 s and a precision of ±0.1 pH units. Measurements of pH were performed on the surface of low-pH cement paste samples after 4, 6, 7 and 8 days of hydration
Capture and characterization of extracellular vesicles by dielectrophoresis
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On-chip differentiation of radially vascularized hepatic cords mimicking the liver lobule
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OnâChip Differentiation of Hepatic Cords with Radial Flow
International audienceDue to a more physiological reproduction of the in vivo situation, liverâonâaâchip devices in recent studies have shown higher sensitivity and accuracy for hepatotoxicity testing compared to traditional in vitro liver models. In this context, this work presents an original microfluidic device mimicking 3D hepatic cords organized radially, like in the liver lobule. Ten cellâculture chambers seeded at a high density are disposed with a parallelized flow that emulates blood flow from the portal triad to the central vein in the liver lobule. Using this device, onâchip differentiation of human HepaRGâHepatoblast (HepaRGâHB) to HepaRGâHepatocytes (HepaRGâHC) has been studied in terms of selfâorganization capabilities, bile canaliculi formation and albumin expression. Our results indicate that due to the design of the cell culture chamber, which mechanically constrains tissue proliferation, and the physiologically relevant microfluidic flow condition used during tissue development, the HepaRGâHBs in the device can proliferate, selfâorganize, and spontaneously differentiate in a DMSO free medium forming long, directional bile canaliculi. On the contrary, under the same conditions, differentiated HepaRGâHC is observed to aggregate without long bile canaliculi and form tissues resembling traditional HepaRGâHC cultures. © 2024 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC