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Over the last decades, metamaterials have been shown to exhibit extraordinary properties. These properties could allow the design of new devices such as negative refractive index lenses, cloaking devices and perfectly flat lenses. This PhD is part of the ANR METAPHOTONIQUE project and its main objective was to study the potential of metamaterials for integrated photonics at telecommunication wavelengths. This required to first better understand the behavior of metamaterials, which led us to study effective index models. The retrieval of effective optical parameters required to be able to simulate the optical response of metamaterials under oblique incidence excitation. Due to this, we had to study and implement such methods for FDTD computations. Our work also showed that asymmetrical metamaterials possessed the ability to make the polarization of guided modes rotate. This allowed us to design and characterize a potential device for integrated photonics, which effectively converts the polarization of guided modes over lengths shorter than half the wavelength. A secondary goal of this PhD was to study the potential compensation of losses occuring within the metallic nanostructures of our metamaterials through the use of materials with gain. Thus, a model allowing us to simulate such materials in FDTD has been implemented, Au cours des dernières décennies, les métamatériaux ont montré qu'ils pouvaient avoir des propriétés étonnantes, permettant d'imaginer et de réaliser des dispositifs tels que des lentilles à indice négatif, des dispositifs de camouflage ou des lentilles parfaitement plates. Aussi, font-ils aujourd'hui l'objet d'une intense recherche. Cette thèse, inscrite dans le projet ANR METAPHOTONIQUE, avait pour objectif principal d'étudier la possibilité d'utiliser des métamatériaux pour l'optique guidée à la longueur d'onde télécom. Ceci a requis une meilleure compréhension du comportement des métamatériaux, ce qui nous a orientés vers l'étude de modèles effectifs. La récupération des paramètres optiques effectifs a nécessité de pouvoir simuler la réponse des métamatériaux sous une illumination en incidence oblique, ce qui a requis l'implémentation de telles méthodes en FDTD. Aux cours de nos travaux, nous avons aussi mis en évidence un phénomène de rotation de la polarisation de modes guidés suite à leur interaction avec des métamatériaux asymétriques. Nous avons alors pu concevoir et caractériser un dispositif pour l'optique guidée destiné faire tourner la polarisation de la lumière sur une longueur deux fois plus courte que la longueur d'onde. Enfin, un objectif secondaire a été de déterminer si les pertes dues à la présence de nanostructures métalliques dans nos métamatériaux pouvaient être compensées grâce à l'utilisation de matériaux à gain. Un modèle permettant de décrire de tels matériaux en FDTD a donc été étudié et implémenté

The fragility and plasticity of visual function in children necessitates early detection and treatment of visual disorders. New approaches such as portable automatic refraction, tonometry and digital fundus examination have improved the quality of screening The problem now is a lack of ophthalmologists. One possible solution is to redefine the role of orthoptists. The waiting time for an ophthalmologist appointment is very long in some parts of France (up to a year), because of a training quota established in the 1980s, as well as retirements (average age 52 years), and a concentration of specialists in the south of France and around medical schools. Today, France trains only 80 specialists per year, whereas twice as many are needed Anglo-Saxon countries (US, Canada, United Kingdom) have created a profession--the optometrist--that is intermediate between the optician and the ophthalmologist. This profession is not recognized in France, yet optometrists are capable of detecting many anomalies and quickly referring a child to a specialist.

In order to model correctly the evaporation phenomenon, numerical simulations needs to work with reliable experimental data, allowing to improve the existing models. On the other side, industrialists needs to realize in situ measurements, with experimental techniques that apply to real conditions. This is the framework of this thesis. The main work has been to prove that measurements with rainbow refractometry on unique droplets in a flow were possible, obtain the evaporation rate from those measurements, and prove their stability.The use of a specific setup, most of the time used in PIV, allowed us to realize acquisitions of couple images with a temporal delay. A very fine method for the measurement of variation of diameter has been introduced, allowing the measurement of instantaneous evaporation rate of unique droplets in a flow, using the ripple structure phase shift.; Afin de modéliser correctement les phénomènes liés à l'évaporation, les numériciens souhaitent obtenir des mesures expérimentales fiables, leur permettant d'améliorer leurs modèles. A l'opposé, de nombreux industriels souhaitent pouvoir réaliser des mesures in situ, avec des techniques expérimentales appliquées aux conditions réelles.C'est dans ce cadre que s'est inscrite cette thèse. L'objectif principal, a été de démontrer la faisabilité, et la stabilité, de mesures en réfractométrie d'arc-en-ciel sur des gouttes uniques en écoulement afin d'obtenir le taux d'évaporation de ces gouttes.L'utilisation d'un dispositif dédié habituellement à la PIV a servi à réaliser des acquisitions de couples d'images, séparées par un délai temporel variable. Une méthode très fine de la mesure de variation de diamètre a été introduite, autorisant la mesure du taux d'évaporation instantané d'une goutte en écoulement par le biais du déphasage de la structure de ripple.

In order to model correctly the evaporation phenomenon, numerical simulations needs to work with reliable experimental data, allowing to improve the existing models. On the other side, industrialists needs to realize in situ measurements, with experimental techniques that apply to real conditions. This is the framework of this thesis. The main work has been to prove that measurements with rainbow refractometry on unique droplets in a flow were possible, obtain the evaporation rate from those measurements, and prove their stability.The use of a specific setup, most of the time used in PIV, allowed us to realize acquisitions of couple images with a temporal delay. A very fine method for the measurement of variation of diameter has been introduced, allowing the measurement of instantaneous evaporation rate of unique droplets in a flow, using the ripple structure phase shift., Afin de modéliser correctement les phénomènes liés à l'évaporation, les numériciens souhaitent obtenir des mesures expérimentales fiables, leur permettant d'améliorer leurs modèles. A l'opposé, de nombreux industriels souhaitent pouvoir réaliser des mesures in situ, avec des techniques expérimentales appliquées aux conditions réelles.C'est dans ce cadre que s'est inscrite cette thèse. L'objectif principal, a été de démontrer la faisabilité, et la stabilité, de mesures en réfractométrie d'arc-en-ciel sur des gouttes uniques en écoulement afin d'obtenir le taux d'évaporation de ces gouttes.L'utilisation d'un dispositif dédié habituellement à la PIV a servi à réaliser des acquisitions de couples d'images, séparées par un délai temporel variable. Une méthode très fine de la mesure de variation de diamètre a été introduite, autorisant la mesure du taux d'évaporation instantané d'une goutte en écoulement par le biais du déphasage de la structure de ripple.

Non-contact biometers have many advantages including the delegation of tasks to orthoptists. This study analyses the reliability of measurements comparing contact and non-contacts techniques.Comparative measurements were taken on 86 eyes of 45 patients (mean age: 74 years; 44.4 % males) in preoperative phacoemulsification by three orthoptists with experience in this task. Each patient had non-contact measurements (Lenstar LS 900, Haag-Streit) and contact measurements (corneal biometry and ultrasound pachymetry with OcuScan RXP, Alcon) and a keratometry refractometer (TONOREF II, Nidek). The axial length data, pachymetry, power of the intraocular lens (SRK/T formula), anterior chamber depth, and the average keratometry were analyzed by paired comparisons.The non-contact biometer was ineffective in 5.8 % of cases (Parkinson's disease, two cases; dense posterior subcapsular cataracts, three cases). The non-contact pachymetry was statistically significantly higher (546.4 μm vs. 538.6 μm; p0.001). The axial length was significantly longer for the non-contact measurement (23.21 mm vs. 23.05 mm; p0.0001). In 25.9 % of patients, this difference was greater than or equal to 0.3mm and affected the power of the implant chosen. The anterior chamber depth measured on non-contact biometry was statistically greater (3.33 mm vs. 3.03 mm; p0.0001). However, there was no significant difference regarding the average keratometry (43.82 D vs. 43.78 D; p=0327).Besides the infectious benefit for patients, absence of cleaning and decontamination of biometric probes, non-contact measurements using Lenstar are an example of a safe activity that can be delegated to assistants. This technique has been used to optimize the refractive outcome of 25.9 % of our patients undergoing refractive cataract surgery.

Whatever the context is (biotechnology, molecular biology) biochips are now considered as a relevant system to detect biological molecules. The recent idea of a fluid biochip, which relies on the capture of target molecules at a functionalized liquid interface, allows in particular the use of the rheological interfacial properties as a micromechanical diagnostic : a change in the surface rheology can be induced by the hybridization between probe and target molecules. The relevance of such a device in the field of DNA detection is studied experimentally. A meniscus capillary wave net is promoted at the surface of a water sub-phase contained in cylindrical cell submitted to vertical vibration. The geometry of the wave net, which is characterized by two optical techniques, demonstrates a sensitivity to the surface tension and to the rheological interfacial properties. The value of these micromechanical parameters depends on the fact the DNA is single-stranded or double-stranded.; Quel que soit le contexte biotechnologique ou biomoléculaire, les biopuces se sont rapidement imposées comme système de détection de molécules biologiques. Le concept récent de biopuce fluide, qui consiste à capturer les molécules d'intérêt à une interface fluide fonctionnalisée, offre entre autres perspectives la possibilité d'utiliser, comme diagnostic micromécanique, les changements de rhéologie interfaciale induits parl'hybridation entre molécules cibles et molécules sondes. La pertinence d'un tel moyen de détection pour des séquences d'ADN, est étudiée expérimentalement. Un réseau d'ondes capillaires de ménisque est engendré à la surface d'une sous-phase aqueuse, contenue dans un récipient cylindrique agité verticalement. Le réseau d'ondes, dont la géométrie est caractérisée conjointement par deux techniques optiques non intrusives, montre à la fois une sensibilité à la tension de surface et aux propriétés rhéologiques interfaciales, qui subissent une évolution différente en présence de brins d'ADN hybridés ou non hybridés.

Whatever the context is (biotechnology, molecular biology) biochips are now considered as a relevant system to detect biological molecules. The recent idea of a fluid biochip, which relies on the capture of target molecules at a functionalized liquid interface, allows in particular the use of the rheological interfacial properties as a micromechanical diagnostic : a change in the surface rheology can be induced by the hybridization between probe and target molecules. The relevance of such a device in the field of DNA detection is studied experimentally. A meniscus capillary wave net is promoted at the surface of a water sub-phase contained in cylindrical cell submitted to vertical vibration. The geometry of the wave net, which is characterized by two optical techniques, demonstrates a sensitivity to the surface tension and to the rheological interfacial properties. The value of these micromechanical parameters depends on the fact the DNA is single-stranded or double-stranded., Quel que soit le contexte biotechnologique ou biomoléculaire, les biopuces se sont rapidement imposées comme système de détection de molécules biologiques. Le concept récent de biopuce fluide, qui consiste à capturer les molécules d'intérêt à une interface fluide fonctionnalisée, offre entre autres perspectives la possibilité d'utiliser, comme diagnostic micromécanique, les changements de rhéologie interfaciale induits parl'hybridation entre molécules cibles et molécules sondes. La pertinence d'un tel moyen de détection pour des séquences d'ADN, est étudiée expérimentalement. Un réseau d'ondes capillaires de ménisque est engendré à la surface d'une sous-phase aqueuse, contenue dans un récipient cylindrique agité verticalement. Le réseau d'ondes, dont la géométrie est caractérisée conjointement par deux techniques optiques non intrusives, montre à la fois une sensibilité à la tension de surface et aux propriétés rhéologiques interfaciales, qui subissent une évolution différente en présence de brins d'ADN hybridés ou non hybridés.

We compared pupil size measurements obtained with the Orbscan and autorefractometer to the Colvard Infrared pupillometer in order to determine their respective clinical advantages.We prospectively measured the pupil diameter in 94 eyes of 47 normal patients using the Colvard device, the Nikon NKR 8000 autorefractometer, and the Orbscan device. For each device, two successive measurements were taken to determine its reproducibility. We also studied the relationship with the contralateral eye (i.e., difference and correlation). The measurements obtained with the different devices in different light intensities were compared and studied using regression analysis.Pupil diameter measured using the Orbscan had the highest reproducibility (mean difference between the two successive measurements: 3.8% or 0.15mm) and showed the smallest difference between the two eyes (5.0% or 0.19mm) and the strongest correlation with the contralateral eye (r=0.93; p0.001). Scotopic Colvard measurements and autorefractometer measurements with low light settings were not significantly different (5.86mm versus 5.86mm; p=0.48). Autorefractometer measurements with low light settings showed the strongest correlation with the scotopic Colvard measurements (r=0.84; p0.001). The Orbscan measurements were less correlated with the scotopic or photopic Colvard measurements (r=0.73; p0.001 and r=0.51; p=0.003, respectively). For the Colvard pupillometer, the correlation between photopic measurements and scotopic measurements was also poor (r=0.51; p0.001).Pupil size measurements with the autorefractometer may be advantageous before refractive surgery. Measuring pupil size in photopic conditions, as with the Orbscan, cannot screen people with large pupils in mesopic conditions.

This habilitation manuscript deals with the optical characterization of multiphase flows. It gathers three types of contributions. The first part concerns the modelling of the light scattering properties of various particles encountered in flows: homogeneous droplets, bubbles and fibres; spherical and cylindrical particles with internal refractive index gradients or coated; ellipsoidal, heterogeneous and irregular particles. These theoretical and numerical works are established in the framework of the Lorenz-Mie theory or with physical or geometrical approximations. The second part introduces the principle of several new optical techniques for the simultaneous characterization of the velocity, the size and material of flowing particles: Dual Bursts and Dual Mode techniques, Phase Doppler interferometry with 3 coherent beams, high resolution diffractometry, rainbow and critical scattering. The third part presents several works completed in collaboration, on subjects connected with: biophysics; combustion; instabilities of capillary and viscous jets, homogeneous and coated; glass-fibre drawing, optical fibres, thermosolutal instabilities and gas-solid circulating fluidized beds flows. This manuscript includes also a summary of my activities of teaching, valorization and management of research, as well as the reproductions of ten articles., Ce manuscrit d'habitation à diriger des recherches porte sur la caractérisation optique des écoulements multiphasiques. Il rassemble trois types de contributions. La première, traite de la modélisation des propriétés de diffusion de la lumière des particules rencontrées dans ces milieux : gouttes, bulles et fibres homogènes ; particules sphériques, fibres et jets à gradient radial d'indice, à coeur ; particules ellipsoïdales, hétérogènes ou irrégulières. Ces développements théoriques et numériques sont basés sur la théorie de Lorenz- Mie ou des modèles asymptotiques : modèle statistique, optique physique et géométrique. La deuxième partie de ce manuscrit, introduit le principe de techniques optiques originales pour la caractérisation simultanée de la vitesse, de la taille et du matériau de particules en écoulement : technique Dual Burst, Dual Mode, Interférométrie phase Doppler à 3 faisceaux cohérents, diffractométrie haute résolution, diffusion critique et arc-en-ciel. La troisième partie présente différents travaux réalisés dans le cadre de collaborations universitaires ou industrielles, sur des sujets aussi variés que la caractérisation des propriétés optiques de globules rouges, la caractérisation de système en combustion, les instabilités de jets capillaires homogènes ou à coeur ; le fibrage du verre à haute température ; les fibres optiques ; l'étude expérimentale d'instabilités thermo-solutales et de l'hydrodynamique d'écoulements gaz-solides en lit fluidisé circulant. Ce manuscrit comprend également un résumé de mes activités d'enseignement, de valorisation et de management de la recherche, ainsi que les reproductions de dix articles.

Scleral indentation is an essential time in conventional retinal detachment surgery. It enables re-establishing retinal contact and to counterbalance vitreal tractions. It can be circular, segmental or radial. Silicone materials are often used.In a prospective study, we followed up 30 eyes of patients who underwent retinal detachment surgery. We analyzed changes in corneal surface using differential map of the corneal (induced astigmatism, meridian axial deviation) and change in the axial length of the globe.Follow-up examination showed corneal astigmatism: 2.62 diopter (D) at one week, 2.37D at one month and 1.80D at 3 months. Corneal axis meridians changed: 25 degrees at one week and 18.6 degrees at 2 months. Axial length was also modified. We observed a lengthening: 1.7mm during the first week which remained unchanged at 1.63 after 2 and 3 months. These changes were studied according to the different techniques used in our study and were compared with results reported in the literature.We think that conventional retinal detachment surgery causes modifications in refractis (induced astigmatism and axial lengthening).

We followed a 45-year-old man who underwent clear cornea phacoemulsification cataract extraction 3 years after radial keratotomy during an 18 month period. We report early and late refractive analysis and corneal topography during the followup period. The patient experienced an hyperopic shift which was different from the aim of 5 diopters due to an early corneal flattening of 3 diopters and an underestimation of the IOL power of 2 diopters using SRKII calculation formula. Corneal flattening regressed after 3 weeks. We recommend that these patients should be informed of an eventual early hyperopic shift and late refractive error, that Binkhorst II or Hoffer-Q intraocular lens calculation formulas be used and keratometry measurements be obtained from computerized videokeratography.

The surgical treatment of intermittent exotropia remains a difficult problem. We present our results about our prismatic approach of the postoperative under- and overcorrections. The treatment of the overcorrections has to adapt to each case but we propose a stereotyped prismatic method (with a total amount of prismatic diopters never exceeding 5PD) to treat the undercorrections. This method is simple and well tolerated for a long term. It is especially useful in the cases of discrepancy between the far and near measurements.

Dosage of lactulose and determination of related sugars (lactose, fructose, galactose, épilactose) were undertaken by high performance liquid chromatography (HPLC). The present note described two modes of detection used simultaneously and compared: refractive index detector (RI) and multiwavelength ultraviolet detector (UV). HPLC is performed with an aminopropylsylil phase as stationary phase and an isocratic mobile phase containing acetonitrile and aqueous sodium phosphate. The results are outlined and discussed.

Analysis of the means by which accuracy of intraocular lens power calculation could be improved with theoretical and linear regression formulas. The postoperative refractive errors with the lenses selected by the surgeon were compared with those observed with the emmetropic calculated power lenses and with a standard 20 diopters lens. A consecutive series of 100 eyes with less than 4.50 diopters of pre-operative myopia or hypermyopia, is evaluated. Postoperative refractive errors are out of the range -4; +4 diopters in 6% for standard lens, 4% for actually implanted lens, and 1% for emmetropic power calculated lens.

Exercise-induced asthma only differs from common asthma in its causative factor. It is a typical asthmatic attack which follows a strenuous and continuous physical exercise lasting 5 to 10 minutes, most often in cold and dry weather. The prevalence of exercise-induced asthma has not yet been firmly established; its pathophysiological mechanisms are still debated, and the respective roles of heat and water losses by the airways are not clearly defined. However, the influence of the type of exercise as a precipitating factor of exercise-induced asthma is now well-known. All things being equal, swimming generates less asthma than running and cycling. This enables the subjects to be directed towards the most suitable sports and encouraged to improve their physical fitness. Drug treatment of exercise-induced asthma must preferentially be preventive; it relies on cromoglycate and beta-2 adrenergic agonists, the latter being also capable of treating acute exercise-induced bronchial obstruction. Education of the patients and their family is also important.