A partitioned approach is studied to solve strongly coupled nonlinear fluid structure interaction problems. The stability, convergence and performance of explicit and implicit coupling algorithms are explored. The partitioned approach allows to re-use existing codes in a more general context. One purpose of this work is to be able to couple them as black-boxes. To that end, the scientific software component framework CTL is considered. Therefore a fluid and a structure component based on existing software are developed and coupled with a master code approach. Computational performance of different remote calls and parallel implementation of components are also depicted herein. The re-use of existing software allows to couple advanced models developed for both sub-problems. In this work, the structure part is solved by the Finite Element Method, with the possibility to use different non-linear and large deformation behaviors. For the fluid part, examples modeled with an arbitrary Lagrangian Eulerian formulation are considered, solved with a finite volume method. The models used are first transient incompressible flows described by the Navier-Stokes equation, then free surface flows. With the latter, the impact of sloshing and breaking waves on model structures can be computed

Cette thèse présente une étude exploratoire de plusieurs aspects du couplage fort lumière-matière dans des matériaux moléculaires. Différentes propriétés héritées d’un tel couplage sont démontrées, ouvrant de nombreuses possibilités d’applications, allant du transfert d’énergie à la génération de signaux optiques non-linéaires et à l’élaboration de réseaux polaritoniques chiraux. Au travers des thématiques abordées, l’idée d’un couplage lumière-matière entrant en compétition avec les différentes fréquences de dissipation des molécules se révèle être cruciale. Ainsi, la prédominance du couplage cohérent au champ électromagnétique apparaît comme un moyen de modifier les propriétés quantiques des états moléculaires, ouvrant la voie à une nouvelle chimie des matériaux en cavité. / This thesis presents an exploratory study of several aspects of strong light-matter coupling in molecular materials. Different properties inherited from such a coupling are demonstrated, opening the way to numerous applications, ranging from energy transfer to the generation of non-linear optical signals and to the development of chiral polaritonic networks. Through the topics covered, the idea of a light-matter coupling strength competing with the different frequencies of relaxation of the molecules proves to be crucial. Thus, the predominance of the coherent coupling to the electromagnetic field appears as a new mean of modifying the quantum properties of molecular systems, opening the way to a new chemistry of materials in optical cavities.

A wide range of non-destructive testing (NDT) methods for the monitoring the health of concrete structure has been studied for several years. The recent rapid evolution of wireless sensor network (WSN) technologies has resulted in the development of sensing elements that can be embedded in concrete, to monitor the health of infrastructure, collect and report valuable related data. The monitoring system can potentially decrease the high installation time and reduce maintenance cost associated with wired monitoring systems. The monitoring sensors need to operate for a long period of time, but sensors batteries have a finite life span. Hence, novel wireless powering methods must be devised. The optimization of wireless power transfer via Strongly Coupled Magnetic Resonance (SCMR) to sensors embedded in concrete is studied here. First, we analytically derive the optimal geometric parameters for transmission of power in the air. This specifically leads to the identification of the local and global optimization parameters and conditions, it was validated through electromagnetic simulations. Second, the optimum conditions were employed in the model for propagation of energy through plain and reinforced concrete at different humidity conditions, and frequencies with extended Debye's model. This analysis leads to the conclusion that SCMR can be used to efficiently power sensors in plain and reinforced concrete at different humidity levels and depth, also validated through electromagnetic simulations. The optimization of wireless power transmission via SMCR to Wearable and Implantable Medical Device (WIMD) are also explored. The optimum conditions from the analytics were used in the model for propagation of energy through different human tissues. This analysis shows that SCMR can be used to efficiently transfer power to sensors in human tissue without overheating through electromagnetic simulations, as excessive power might result in overheating of the tissue. Standard SCMR is sensitive to misalignment; both 2-loops and 3-loops SCMR with misalignment-insensitive performances are presented. The power transfer efficiencies above 50% was achieved over the complete misalignment range of 0°-90° and dramatically better than typical SCMR with efficiencies less than 10% in extreme misalignment topologies.

Dans ce travail de thèse nous avons étudié les propriétés de fluorescence de films minces d’or dopés avec des molécules organiques Nous avons montré par imagerie électroniques MEB et TEM qu’ils sont structurés en agglomérats de nanocristaux (5 à 10nm) recouverts de molécules formant un gap nanométrique. Dans les spectres d’extinction nous avons observé la présence de la résonance plasmon du métal ainsi que d’une autre résonance à 600nm que nous attribuons au plasmon de gap.Les spectres d’émission et d’excitation de fluorescence ont confirmé que ces films dopés fluorescents avec une composante venant de la fluorescence de l’or, et une autre caractéristique de la présence des molécules fluorescentes. Les décalages spectraux en excitation et en émission à la fois de l’or et des molécules sont les signes d’un couplage fort entre leurs états électroniques, ce qui serait en accord avec la très forte concentration de molécules dans le film (1/100 molaire)L’observation non intuitive de la fluorescence des molécules insérées dans la couche d’or aurait pour origine l’augmentation considérable de leur taux radiatifs qui a été récemment observé dans les nanogaps. / In this thesis work we studied the fluorescence properties of gold thin films doped with organic molecules. We have shown by electronic imaging SEM and TEM that they are structured in agglomerates of nanocrystals (5 to 10 nm) covered with molecules forming a nanometric gap. In the quenching spectra we observed the presence of the plasmon resonance of the metal as well as another resonance at 600nm that we attribute to the gap plasmon.The fluorescence emission and excitation spectra confirmed that these fluorescent doped films with a component coming from the fluorescence of gold, and another characteristic of the presence of fluorescent molecules. The spectral shifts in excitation and in emission of both the gold and the molecules are the signs of a strong coupling between their electronic states, which would be in agreement with the very high concentration of molecules in the film (1/100 molar)The non-intuitive observation of the fluorescence of the molecules inserted into the gold layer is due to the considerable increase in their radiative levels that has recently been observed in nanogaps.

The diploma thesis deals with the optical response of resonant infrared antennas on silicon dioxide thin film. At first, theory of electromagnetism at metal/dielectric interfaces is described. In the next part, experimental and numerical methods used in the thesis are described and strong coupling between two systems is explained. In the final part of the thesis, the optical response of resonant infrared antennas on a silicon dioxide thin film is studied by Fourier transform Infrared Spectroscopy and FDTD simulations which both show the strong coupling between localized plasmons and phonons in silicon dioxide.

This diploma thesis deals with numerical simulations of the optical response of plasmonic infrared antennas placed on silicon substrates with thin film of silicon dioxide and subsequently with fitting of scattering spectra by model of coupled harmonic oscillators. In this work, we study an influence of length of antennas on the strength of coupling of localized surface plasmons in the antennas with phonons in silicon dioxide film. Also, the influence of silicon dioxide film thickness on this coupling is investigated.

Dans cette thèse, nous avons étudié les propriétés photoniques et vibrationnelles de monocouches moléculaires auto-assemblées sur graphène et la possibilité d'utiliser des multicouches auto-assemblées de pérylène comme milieu à gain pour l'amplification de plasmons. Le graphène, en tant que matériau transparent et conducteur, a permis pour la première fois de corréler la géométrie du réseau de l’auto-assemblage supramoléculaire avec ses propriétés optiques, grâce à la microscopie à effet tunnel et à des mesures de spectroscopiques optiques et Raman. En comparant plusieurs colorants autoassemblés sur le graphène, nous avons mis en lumière les effets des interactions intermoléculaires et des interactions colorant-graphène sur le spectre d'absorption du colorant adsorbé. Le transfert d'énergie rapide des colorants vers la couche degraphène par les mécanismes de Förster et de Dexter empêche toute relaxation radiative du colorant..Néanmoins, nous avons démontré la première fonctionnalisation fluorescente non-covalente du graphène par une monocouche de colorants autoassemblée en mettant en place une stratégie à base d’espaceurs. Nous avons exploité l’extinction rapide de la fluorescence des colorants par le graphène pour étudier les spectres Raman des auto-assemblages moléculaires sur graphène, et nous avons révélé l'apparition d'un mode vibrationnel couplé entre les molécules adsorbées et le substrat de graphène. Nous avons démontré le régime de couplage fort entre un auto-assemblage tri-dimensionnel de pérylène et un plasmon polariton de surface en optimisant l'orientation et l'organisation des molécules de colorant par rapport au champ électrique du mode de plasmon. Nous avons prouvé que les milieux de gain auto-assemblés en agrégats-J peuvent théoriquement conduire à des milieux de gain efficaces pour l'amplification de plasmons. Cependant, nous avons révélé expérimentalement que les recombinaisons exciton-exciton limitent le taux de pompage à des fluences élevées dans ces milieux denses. / In this work, we have studied thephotonic and vibrational properties of selfassembled molecular monolayers on graphene and the possibility to use perylene self-assembled multilayers as a gain medium for plasmon amplification. Graphene, as a transparent and conductive material, has offered for the first time to correlate the self-assembly structure as deduced from scanning tunneling microscopy to photonic properties as analyzed by optical and Raman spectroscopy measurements. By comparing several self-assembled dyes on graphene we have shed lighton how intermolecular and dye-graphene interactions modify the absorption spectrum of the adsorbed dye.Fast Förster and Dexter energy transfer from the adsorbed dyes to the graphene layer prevent any radiative decay of the dye.Nevertheless, we have demonstrated the first fluorescent non-covalent functionalization of graphene by a supramolecular self-assembled monolayer using a spacer approach.We have exploited the fast dye fluorescence quenching by graphene to study Raman spectra of self-assembled dye on graphene, and we have shown the appearance of a coupled vibrational mode between the adsorbed molecules and the graphene substrate. We have demonstrated the strong couplingregime between a three-dimensional perylene self-assembly and a propagating plasmon polariton by optimizing the orientation and the organisation of the dye molecules compared to the electric field of the plasmon mode. We have shown that J-aggregated self-assembled gain media may theoretically lead to efficient gain media for plasmon amplification. However, we experimentally demonstrated that exciton-exciton recombination limits the achievable pumping rate at high fluences in such dense media.

Les polaritons inter-sous-bandes, observés pour la première fois il y a une quinzaine d’années, sont des quasi-particules dont de nombreuses propriétés restent encore à découvrir. La recherche dans ce domaine se focalise actuellement sur la réalisation de condensats de Bose-Einstein. Une telle découverte pourrait révolutionner l’optoélectronique du moyen infra-rouge jusqu’au THz ouvrant la voie à l’instauration de nouveaux concepts de sources lumineuses,de détecteurs ou de systèmes logiques en couplage fort. Dans cette quête, le choix de la cavité résonnante est critique. Dans ce manuscrit nous proposons d’utiliser des cavités métal-isolant-métal (M-I-M) avec un réseau dispersif sur le métal supérieur. Ce type de cavité,conservant un confinement élevé entre les deux plans métalliques, offre de nombreuses possibilités d’ajustement de la résonance de cavité : via la géométrie de la cavité ( épaisseur de la cavité, période et recouvrement du réseau) ainsi que par le couplage de la lumière avec la cavité (vecteur d’onde incident). Les cavités M-I-M dispersives ouvrent donc un nouveau champ d’exploration des polaritons inter-sous-bande. Dans un premier temps nous avons introduit ces cavités dans le domaine du THz afin d’étudier les phénomènes de relaxation polariton-polariton. Un système expérimental dédié à cette exploration a été conçu pour mesurer la réflectivité des polaritons THz avec une fine résolution en angle. Dans une second temps, des capteurs moyen infrarouge en couplage fort avec une cavité M-I-M dispersive ont été conçus, fabriqués et mesurés dans le but d’explorer la génération de photo-courant à partir de polaritons et d’utiliser le couplage fort pour dissocier l’ énergie de détection de l’énergie d’activation. Cette seconde étude s’inscrit dans l’objectif de pompage électrique des polaritons ISB. Parallèlement à l’étude des polaritons, nous avons également participé au développement de techniques(interféromètre Gires-Tournois et revêtement anti-réflection) pour compresser les impulsions optiques de lasers à cascade quantique THz. / After fifteen years of intersubband polaritons development some of the peculiar properties of these quasi-particles are still unexplored. A deeper comprehension of the polaritons is needed to access their fundamental properties and assess their applicative potential as efficient emitters or detectors in the mid-infrared and THz.In this manuscript we used Metal-Insulator-Metal (MI-M) cavities with a top metal periodic grating as a platform to deepen the understanding of ISB polaritons.The advantages of M-I-M are twofold : first they confine the TM00 mode, second the dispersion of the cavity -over a large set of in-plane wave-vectors- offers various experimental configurations to observe the polaritons in both reflection and photo-current. We reexamined the properties of ISB polaritons in the mid-infrared and in the THz using these resonators. In the first part, we explore the implementation of dispersive M-I-M cavities with THz intersubband transitions. In the THz domain, the scattering mechanisms of the THz ISB polaritons need to be understood. The dispersive cavity is a major asset to study these mechanisms because it provides more degrees of freedom to the system. For this purpose, we fabricated a new experimental set-up to measure the polariton dispersion at liquid Helium temperature. After the characterization of the polaritons in reflectivity, a pump-probe experiment was performed on the polaritonic devices. The second part of this manuscript presents the implementation of M-I-M dispersive cavities with abound-to-quasi-bound quantum well infrared photo detector designed to detect in strong coupling. Beyond electrical probing of the polaritons, the strong coupling can disentangle the frequency of detection from the thermal activation energy and reduce the dark current at a given frequency. In parallel to the exploration of THz polaritons, we developed two techniques (Gires-Tournois Interferometer and Anti-reflection coating) in order to shorten the pulses of THz quantum cascade lasers with metal-metal waveguides.

Disorder-induced heating (DIH) is a nonequilibrium, ultrafast relaxation process that occurs when laser-cooled atoms are photoionized to make an ultracold plasma. Its effects dominate the ion motion during the first 100 ns of the plasma evolution. Using tools of atomic physics we study DIH with ns time resolution for different plasma densities and temperatures. By changing the frequency of the laser beam we use to probe the ions, we map out the time evolution of the velocity distribution. We can compare this to a fluorescence simulation in order to more clearly determine the relationship between the fluorescence signal and the velocity distribution. In this study we observe and characterize effects due to electron screening on the ions during the equilibration process.

Ultracold neutral plasmas provide a platform for studying transport properties in an idealized environment. In this dissertation, transport properties in a Ca$^+$/Yb$^+$ dual species ultracold neutral plasma and a Ca$^+$ magnetized ultracold neutral plasma are studied. In dual species plasmas, we study ion-ion temperature relaxation. We compare measured relaxation rates with atomistic simulations and a range of popular theories. Our work validates the assumptions and capabilities of molecular dynamic simulations and invalidates theoretical models in this regime. This work illustrates an approach for precision determinations of detailed material properties in Coulomb mixtures across a wide range of conditions. We also study plasma expansion in single species plasma in the presence of a strong uniform magnetic field. We find that the asymptotic expansion velocity falls exponentially with magnetic field strength, which disagrees with a previously published ambipolar diffusion model. In the parallel direction, plasma expansion is driven by electron pressure. However, in the perpendicular direction, no plasma expansion is observed at large magnetic field strengths.