This dissertation presents the contributions and the research conducted in developing and implementing Microwave Tomography (MWT) systems. MWT is an imaging modality which aims to interrogate an object of interest by microwave energy, and quantitatively “find” the interior spatial distribution of its dielectric properties using field measurements taken outside the object. Due to the inherent non-linearity of the MWT problem, a substantial amount of electromagnetic scattering data is required to ensure a robust inversion and quantitatively accurate imaging results. This research benefits a variety of applications including biomedical imaging, industrial non-destructive testing, and security applications. Developing a MWT system, requires many critical components including the bandwidth and polarization purity of the collected fields as well as calibration of the fields scattered by the object of interest. Two generations of MWT systems were designed, implemented, calibrated and tested at the University of Manitoba (UM). These systems aim different approaches for near-field measurements which are referred to as the direct and indirect methods. With regard to the antenna design, a novel methodology applicable to broadband planar antennas is introduced. This technique is based on a combination of field modelling, herein, the finite element method and transmission line modelling. In the first generation of the UM MWT systems, a suitable antenna system was utilized. The system under study was a prototype, where twenty-four co-resident antennas encircle the object of interest to directly measure the fields. In the second generation of the UM MWT systems, the feasibility of using a novel technique to indirectly measure the fields by a secondary array of near-field scatterer probes was studied. The technique is based on the Modulated Scatterer Technique (MST). In this system, antennas are called ``collectors", since the role of antennas are changed to collecting probes' scattered fields. A number of PIN diodes were utilized to activate the probes. Finally, the capability of the probe system was investigated and its performance with the previously constructed tomography systems was compared. Various dielectric phantoms were utilized to test the accuracy of the systems.

Near-field optical microscopy has attracted remarkable attention, as it is the only technique that allows the investigation of local optical properties with a resolution far below the diffraction limit. Especially, the scattering-type near-field optical microscopy allows the nondestructive examination of surfaces without restrictions to the applicable wavelengths. However, its usability is limited by the availability of appropriate light sources. In the context of this work, this limit was overcome by the development of a scattering-type near-field microscope that uses a widely tunable free-electron laser as primary light source. In the theoretical part, it is shown that an optical near-field contrast can be expected when materials with different dielectric functions are combined. It is derived that these differences yield different scattering cross-sections for the coupled system of the probe and the sample. Those cross-sections define the strength of the near-field signal that can be measured for different materials. Hence, an optical contrast can be expected, when different scattering cross-sections are probed. This principle also applies to vertically stacked or even buried materials, as shown in this thesis experimentally for two sample systems. In the first example, the different dielectric functions were obtained by locally changing the carrier concentration in silicon by the implantation of boron. It is shown that the concentration of free charge-carriers can be deduced from the near-field contrast between implanted and pure silicon. For this purpose, two different experimental approaches were used, a non-interferometric one by using variable wavelengths and an interferometric one with a fixed wavelength. As those techniques yield complementary information, they can be used to quantitatively determine the effective carrier concentration. Both approaches yield consistent results for the carrier concentration, which excellently agrees with predictions from literature. While the structures of the first system were in the micrometer regime, the capability to probe buried nanostructures is demonstrated at a sample of indium arsenide quantum dots. Those dots are covered by a thick layer of gallium arsenide. For the first time ever, it is shown experimentally that transitions between electron states in single quantum dots can be investigated by near-field microscopy. By monitoring the near-field response of these quantum dots while scanning the wavelength of the incident light beam, it was possible to obtain characteristic near-field signatures of single dots. Near-field contrasts up to 30 % could be measured for resonant excitation of electrons in the conduction band of the indium arsenide dots. / Die optische Nahfeldmikroskopie hat viel Beachtung auf sich gezogen, da sie die einzige Technologie ist, welche die Untersuchung lokaler optischer Eigenschaften mit Auflösungen unterhalb der Beugungsgrenze ermöglicht. Speziell die streuende Nahfeldmikroskopie erlaubt die zerstörungsfreie Untersuchung von Oberflächen ohne Einschränkung der verwendbaren Wellenlängen. Die Nutzung ist jedoch durch das Vorhandensein entsprechender Lichtquellen beschränkt. Im Rahmen dieser Arbeit wurde diese Beschränkung durch Entwicklung eines streuenden Nahfeldmikroskops überwunden, das einen weit stimmbaren Freie-Elektronen-Laser als primäre Lichtquelle benutzt. Im theoretischen Teil wird gezeigt, dass ein optischer Kontrast erwartet werden kann, wenn Materialien mit unterschiedlichen Dielektrizitätskonstanten kombiniert werden. Es wird hergeleitet, dass diese Unterschiede in unterschiedlichen Streuquerschnitten für das gekoppelte System aus Messkopf und Probe resultieren. Diese Streuquerschnitte definieren die Stärke des Nahfeldsignals, welches auf unterschiedlichen Materialien gemessen werden kann. Ein optischer Kontrast kann also erwartet werden, wenn unterschiedliche Streuquerschnitte untersucht werden. Dass dieses Prinzip auch auf übereinander geschichtete oder sogar verborgene Strukturen angewendet werden kann, wird in dieser Doktorarbeit an zwei Probensystemen experimentell gezeigt. Im ersten Beispiel wurden die unterschiedlichen Dielektrizitätskonstanten durch örtliches Ändern der Ladungsträgerdichte in Silizium durch Bor-Implantation erreicht. Es wird gezeigt, dass die Dichte der freien Ladungsträger an Hand des optischen Kontrastes zwischen implantiertem und reinem Silizium ermittelt werden kann. Zu diesem Zweck wurden zwei unterschiedliche Ansätze verwendet, ein nicht-interferometrischer mittels variabler Wellenlängen und ein interferometrischer mit einer konstanten Wellenlänge. Weil diese Techniken gegensätzliche Informationen liefern, können sie genutzt werden, um die effektive Ladungsträgerdichte quantitativ zu bestimmen. Beide Ansätze lieferten konsistente Resultate für die Trägerdichte, welche sehr gut mit den Vorhersagen der Literatur übereinstimmt. Während die Strukturen im ersten Beispiel im Mikrometer-Bereich lagen, wird die Möglichkeit, verborgene Nanostrukturen zu untersuchen, an Hand einer Probe mit Indiumarsenid Quantenpunkten demonstriert. Diese sind von einer dicken Schicht Galliumarsenid bedeckt. Zum ersten Mal wird experimentell gezeigt, dass Übergänge zwischen Elektronenzuständen in einzelnen Quantenpunkten mit Nahfeldmikroskopie untersucht werden können. Durch die Messung der Nahfeld-Antwort der Quantenpunkte unter Änderung der Wellenlänge des eingestrahlten Lichtes war es möglich, charakteristische Nahfeld-Signaturen der einzelnen Quantenpunkte zu erhalten. Nahfeld-Kontraste bis zu 30 Prozent konnten für die resonante Anregung der Elektronen im Leitungsband der Indiumarsenid Punkte beobachtet werden.

Les nanocavités optiques sur puces sont devenues aujourd'hui des objets de base pour le piégeage et la manipulation d'objets colloïdaux. Nous étudions dans cette thèse des nanocavités comme briques de bases du piégeage et de la manipulation par forces optiques. La preuve de concept du piégeage de microsphères diélectriques apparaît comme le point de départ de l'élaboration d'un laboratoire sur puce. Dans le premier chapitre nous parcourons la bibliographie de l'utilisation des forces optiques en espace libre et en milieu confiné pour le piégeage de particules. Le second chapitre présente les dispositifs expérimentaux pour la caractérisation des nanocavités et les outils mis en place pour les mesures optiques en présence de particules colloïdales. Le troisième chapitre explique la preuve de concept du piégeage de particules de polystyrène de 500 nm, 1 et 2 µm. Dans le chapitre qui suit nous analysons le piégeage de particules en fonction de la puissance injectée dans la cavité. Le chapitre cinq décrit quelques exemples des possibilités de fonctions de manipulation de particules grâce à des cavités couplées. Enfin, dans le dernier chapitre nous montrons les assemblages de particules sur les différents types de cavités étudiées dans cette thèse. / On chips optical nanocavities have become useful tools for trapping and manipulation of colloidal objects. In this thesis we study the nanocavities as building blocks for optical forces, trapping and handling of particles. Proof of concept of trapping dielectric microspheres appears as the starting point of the development of lab on chip. In the first chapter we go through the literature of optical forces in free space and integrated optics. The second chapter presents the experimental tools for the characterization of nanocavities and the set-up developed to perform optical measurements with the colloidal particles. The third chapter describes the proof-of-concept trapping of polystyrene particles of 500 nm, 1 and 2 µm. In the following chapter we analyze the particle trapping as function of the injected power into the cavities. The chapter five gives some examples of the possibilities of particles handling functions with coupled cavities. Eventually, in the last chapter we show assemblies of particles on different geometry of cavities studied in this thesis.

La RFID est une technologie majeure qui connaît depuis plus d'une dizaine d'années un essor considérable en termes d'applications. Cependant son déploiement à grande échelle reste limité par des plusieurs verrous technique et technologique par lesquels la portée de lecture des tags et leur forte sensibilité à l'environnement de l'application. Le travail engagé dans cette thèse vise le développement des nouvelles antennes lecteurs pour systèmes RFID UHF champ proche. Ce type de système exploite la bande UHF de la RFID en zone de champ proche pour la traçabilité des cibles de taille miniature sur une zone proche du lecteur avec une portée limitée. Les tags se trouvant au delà de cette portée ne doivent pas être détectés par le lecteur. L'objectif dans ce travail est d'apporter des solutions au niveau des antennes lecteurs également celles du tag pour assurer une détection des tags sur une zone confinée de l'espace. Actuellement, moyennant l'utilisation d'un tag sous forme de boucle (1*1 cm²), il est possible de lire ce dernier en contact, c'est à dire dans la zone 0 – 10 cm. Il fallait donc pouvoir assurer une lecture fiable (de type couplage EM) pour une portée s'étendant d'une dizaine de centimètres. Les antennes lecteurs champ proche développés dans ce travail sont en mesure d'assurer une zone de lecture limitée (20 à 35 cm) qui s'étend sur une dizaine de centimètres de côté. / RFID is one of the most popular technologies in this decade. However, its deployment at a high scale is limited by several technical and technological limitations as the read range of tags and their sensitivity to the application's environment. In this thesis we focus on the development of new reader antennas for Near Field UHF RFID systems. This type of system uses the UHF RFID band in near field zone for the traceability of miniature size targets on an area near the reader with a limited zone. Tags being outside this zone should not be detected by the reader .One of the objective of this thesis is to provide solutions in terms of readers and tag antennas to ensure detection tags on a confined area of space. Actually, we can read loop RFID tag (1*1 cm²) in contact (read range 0-10 cm). So we have to be able to ensure a good reading of tag (EM coupling) in a range from few centimeters to meters. Near field reader antenna developed in this thesis work, has a limited range between 20 and 30 cm with a large reading zone.

In 1865 Maxwell outlined the theoretical framework for electromagnetic field propagation. Since then many important developments have been made in the field, with an emphasis on systems using high frequencies for long-range interactions. It was not until recent years that applications based on short-range inductive coupling demonstrated the advantages of using low frequency transmissions with magnetic fields to transfer power and information. This thesis investigates magnetic transmissions in the near-field and the possibility of producing induced voltages in printed circuit boards. A near-field magnetic induction system is designed to generate a magnetic flux in the very low frequency region, and used experimentally to evaluate circuit board induction in several interesting environments. The resulting voltages are measured with digital signal processing techniques, using Welch’s method to estimate the spectrum of the received voltage signal. The results show that the amount of induced voltage is proportional to the inverse cube of the transmission distance, and that the system is able to achieve a maximum induced voltage of 65 \micro V at a distance of 2.5 m and under line-of-sight conditions. It is also concluded that conductive obstructions, electromagnetic shielding and background noise all have a large impact on the obtained voltage, either cancelling the signal or causing it to fluctuate.

ANDRADE, Nádia Ferreira de. Propriedades vibracionais e estruturais de cadeias lineares de carbono. 2014. 213 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2014. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2016-01-05T19:46:56Z No. of bitstreams: 1 2014_tese_nfandrade.pdf: 12228920 bytes, checksum: 9f6aef6ce2c60c7d88f7ecb59b39e43f (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2016-01-05T19:55:18Z (GMT) No. of bitstreams: 1 2014_tese_nfandrade.pdf: 12228920 bytes, checksum: 9f6aef6ce2c60c7d88f7ecb59b39e43f (MD5) / Made available in DSpace on 2016-01-05T19:55:18Z (GMT). No. of bitstreams: 1 2014_tese_nfandrade.pdf: 12228920 bytes, checksum: 9f6aef6ce2c60c7d88f7ecb59b39e43f (MD5) Previous issue date: 2014 / We present a study of linear carbon chains encapsulated in multi-wall carbon nanotubes (Cn@MWCNT) using electron microscopy and Raman spectroscopy in ambient and extreme conditions. The linear chains were characterized by resonance Raman, thermal analysis, ion bombardment and using high resolution and scanning transmission electron microscopy. The HRTEM images obtained here shown the chain within the innermost MWCNT and in this work we obtain the first image of ``cross-section$"$ described for this system Cn@MWCNT. A Raman experiment was carried out in high pressure conditions (from 0 to 9.54 GPa) using a paraffin oil as pressure transmitting medium.The G band frequency of nanotube increase as pressure increase while the C-C stretching mode of linear carbon chain decreases. Theoretical results based on atomistic simulations allowed an understanding of vibrational behavior of the chains. Furthermore, we conducted works that involved instrumentation in order to set in the Department of Physics of the Federal University of Ceara, the instrumentation needed for the development of a device that enables to perform Raman spectroscopy and AFM measurements. For this purpose is necessary to integrate a scan-head, a controller system that controls the probe scan-head and an optical system that communicates with an APD (avalanche photodiode device), responsible for carrying the images with a spectrometer dedicated for obtaining Raman spectra. The system is functional as regards the ability to perform confocal measurements and ready for setting the near field measurements. / Apresentamos um estudo de cadeias lineares de carbono encapsuladas em nanotubos de carbono de paredes múltiplas (Cn@MWCNT) utilizando microscopia eletrônica e espectroscopia Raman em condições ambientes e extremas. As cadeias lineares foram caracterizadas por espectroscopia Raman ressonante, análise térmica, bombardeamento de íons e com microscopia eletrônica de transmissão. As imagens de alta resolução aqui obtidas mostraram a presença das cadeias dentro do tubo mais interno do MWCNT e neste trabalho obtivemos a primeira imagem de "seção transversal" descrita na literatura para um sistema deste tipo. Um experimento Raman foi conduzido em condições de altas pressões (0 - 9,54 GPa), utilizando um óleo de parafina como meio transmissor de pressão. A frequência da banda G dos nanotubos aumentou com o aumento da pressão enquanto o modo de estiramento C-C das cadeias de carbono lineares diminuiu. Resultados teóricos baseados em simulações atomísticas permitiram uma compreensão do comportamento vibracional da cadeia. Além disso, realizamos trabalhos que envolveram instrumentação afim de instalar no Departamento de Física da Universidade Federal do Ceará toda a instrumentação necessária para o desenvolvimento de um equipamento que permite realizar espectroscopia Raman e medidas de microscopia de força atômica (AFM). Para isto, é necessário integrar uma "scan-head", um sistema controlador que controla a sonda da "scan-head" e um sistema óptico que se comunica com uma APD (dispositivo fotodiodo avalanche) responsável pela aquisição das imagens, com um espectrômetro dedicado à obtenção dos espectros Raman. O sistema ficou funcional no que diz respeito a capacidade de executar medidas confocal e está pronto para a realização de medidas de campo próximo.

Dans cette thèse, nous associons mesures expérimentales et modélisation des données pour étudier l'émission spontanée d'émetteurs fluorescents en environnement nano-structuré. Le mémoire est organisé en deux parties.Dans la première partie, nous étudions le transfert d'énergie entre émetteurs fluorescents en environnement plasmonique et sur des distances micrométriques. Pour commencer, nous caractérisons le transfert d'énergie entre deux ensembles d'émetteurs situés en champ proche d'une surface d'argent. Nous déterminons ainsi la dépendance en distance du taux de transfert d'énergie sur des distances micrométriques. Nous couplons ensuite une boite quantique et une bille fluorescente à un nano-fil d'argent et nous étudions le transfert d’énergie entre ces deux émetteurs, distants de plusieurs micromètres. Nous démontrons notamment le clignotement corrélé de ces deux émetteurs grâce à l'étude de la fonction de corrélation de leur intensité de fluorescence.Dans la seconde partie, nous sondons les variations spatiales de densité locale d'états électromagnétiques induites par des environnements nano-structurés grâce à différentes techniques de microscopie à super-résolution. A l'aide d'un microscope à balayage, nous réalisons tout d’abord une étude en trois dimensions de l’interaction de champ proche entre une bille fluorescente et différentes antennes en silicium. Nous introduisons ensuite une technique stochastique permettant de déterminer expérimentalement la position et le taux d'amortissement de molécules uniques photo-activées, avec une précision de localisation de l'ordre de 10 nm. Enfin, nous utilisons l'information de Fisher afin d'estimer les bornes inférieures de l'erreur type des estimations de positions et de taux d'amortissement réalisées dans le cadre de mesures sur molécules uniques. / In this thesis, we perform experimental measurements and data modelling to investigate spontaneous emission of fluorescent emitters in nanostructured environments. The manuscript is organised into two main parts.In the first part, we study micrometre-range energy transfer between fluorescent emitters in plasmonic environments. First of all, we characterise plasmon-mediated energy transfer between ensembles of fluorescent emitters located in the near field of a silver film. We thus determine the distance dependence of the energy transfer rate over micrometre distances. We then couple a single quantum dot and a fluorescent nanobead to a silver nanowire and we study evidences of the energy transfer between the two emitters, separated by several micrometres. We notably demonstrate a correlated blinking of the two emitters through the study of the correlation function of their fluorescence intensity.In the second part, we probe sub-wavelength spatial variations of the local density of electromagnetic states induced by nanostructured environments by means of different super-resolution microscopy techniques. To start with, we perform a three-dimensional study of the near-field interaction between a fluorescent nanobead and different silicon nanoantennas using a scanning-probe microscope. We then introduce a stochastic technique to experimentally determine the position and the fluorescence decay rate of single photo-activated molecules, with a localisation precision of the order of 10 nm. Finally, we use the Fisher information to estimate lower bounds on the standard errors on position and decay rate estimates performed in the context of single-molecule microscopy.

Le thermo-photovoltaïque (TPV), conversion du rayonnement thermique par des cellules photovoltaïques (PV), est un dispositif qui a suscité un intérêt croissant depuis deux décennies, notamment pour son efficacité supérieure à celle de la conversion photovoltaïque classique. Ceci est essentiellement dû à l'accord entre le spectre du rayonnement de la source thermique et le spectre de conversion de la cellule PV. Les rendements maximaux sont obtenus pour des sources thermiques cohérentes, émettant dans une gamme spectrale étroite, énergétiquement au-dessus de l'énergie de la bande interdite de la cellule PV. On propose dans ce travail d'appliquer une méthode d'optimisation stochastique, en l'occurrence l'optimisation par essaims de particules, pour concevoir et optimiser de telles sources. On aboutit alors à des structures unidimensionnelles simples, à base de films minces de diélectriques, métaux et de semi-conducteurs. Les propriétés radiatives de ces sources, stables pour des températures allant jusqu'à 1000 K, sont aisément contrôlables à l'aide de paramètres simples comme les épaisseurs des films ou la concentration de dopage. Finalement, on propose une étude d'optimisation paramétrique des propriétés optiques des matériaux susceptibles de maximiser l'échange radiatif en champ proche entre deux milieux plans semi-infinis. Cette étude aboutit à un outil pratique, sous forme d'abaques, permettant de guider le choix des matériaux pertinents afin de maximiser les puissances au même temps que l'efficacité des systèmes TPV nanométriques. / Thermo-photovoltaic conversion of thermal radiation is a concept that has been thoroughly investigated during the two last decades because of its high efficiency when compared to classical photovoltaics (PV). These high performances are mainly due to the good-matching between the thermal source radiation spectrum and the PV cell conversion spectrum. Maximal efficiencies areobtained with coherent sources that emit in narrow spectral bands, just above the band gap energy of the cell. In this report, a stochastic method to design and optimize such sources, the particle swarm optimization in this case, is firstly presented. This method leads to simple one-dimensional structures, composed of thin films of dielectrics, metals and semiconductors. The radiativeproperties of these sources are easily tunable with control parameters as simple as films thicknesses and doping concentrations. They are stable at high temperatures up to 1000 K. Second, a parametric optimization study of usual materials optical properties models (Drude and Lorentz) is presented in order to maximize radiative heat transfer between semi-infinite planes separated by nanometric gaps. This leads to a simple tool in the form of abacuses which would guide the choice of relevant materials to maximize the output power of nano thermo-photovoltaic devices.

ANDRADE, Nádia Ferreira de. Propriedades vibracionais e estruturais de cadeias lineares de carbono. 2015. 213 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-10-26T18:07:30Z No. of bitstreams: 1 2015_tese_nfandrade.pdf: 12228920 bytes, checksum: 9f6aef6ce2c60c7d88f7ecb59b39e43f (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-10-26T18:14:26Z (GMT) No. of bitstreams: 1 2015_tese_nfandrade.pdf: 12228920 bytes, checksum: 9f6aef6ce2c60c7d88f7ecb59b39e43f (MD5) / Made available in DSpace on 2015-10-26T18:14:26Z (GMT). No. of bitstreams: 1 2015_tese_nfandrade.pdf: 12228920 bytes, checksum: 9f6aef6ce2c60c7d88f7ecb59b39e43f (MD5) Previous issue date: 2015 / We present a study of linear carbon chains encapsulated in multi-wall carbon nanotubes (Cn@MWCNT) using electron microscopy and Raman spectroscopy in ambient and extreme conditions. The linear chains were characterized by resonance Raman, thermal analysis, ion bombardment and using high resolution and scanning transmission electron microscopy. The HRTEM images obtained here shown the chain within the innermost MWCNT and in this work we obtain the first image of ``cross-section$"$ described for this system Cn@MWCNT. A Raman experiment was carried out in high pressure conditions (from 0 to 9.54 GPa) using a paraffin oil as pressure transmitting medium.The G band frequency of nanotube increase as pressure increase while the C-C stretching mode of linear carbon chain decreases. Theoretical results based on atomistic simulations allowed an understanding of vibrational behavior of the chains. Furthermore, we conducted works that involved instrumentation in order to set in the Department of Physics of the Federal University of Ceara, the instrumentation needed for the development of a device that enables to perform Raman spectroscopy and AFM measurements. For this purpose is necessary to integrate a scan-head, a controller system that controls the probe scan-head and an optical system that communicates with an APD (avalanche photodiode device), responsible for carrying the images with a spectrometer dedicated for obtaining Raman spectra. The system is functional as regards the ability to perform confocal measurements and ready for setting the near field measurements. / Apresentamos um estudo de cadeias lineares de carbono encapsuladas em nanotubos de carbono de paredes múltiplas (Cn@MWCNT) utilizando microscopia eletrônica e espectroscopia Raman em condições ambientes e extremas. As cadeias lineares foram caracterizadas por espectroscopia Raman ressonante, análise térmica, bombardeamento de íons e com microscopia eletrônica de transmissão. As imagens de alta resolução aqui obtidas mostraram a presença das cadeias dentro do tubo mais interno do MWCNT e neste trabalho obtivemos a primeira imagem de "seção transversal" descrita na literatura para um sistema deste tipo. Um experimento Raman foi conduzido em condições de altas pressões (0 - 9,54 GPa), utilizando um óleo de parafina como meio transmissor de pressão. A frequência da banda G dos nanotubos aumentou com o aumento da pressão enquanto o modo de estiramento C-C das cadeias de carbono lineares diminuiu. Resultados teóricos baseados em simulações atomísticas permitiram uma compreensão do comportamento vibracional da cadeia. Além disso, realizamos trabalhos que envolveram instrumentação afim de instalar no Departamento de Física da Universidade Federal do Ceará toda a instrumentação necessária para o desenvolvimento de um equipamento que permite realizar espectroscopia Raman e medidas de microscopia de força atômica (AFM). Para isto, é necessário integrar uma "scan-head", um sistema controlador que controla a sonda da "scan-head" e um sistema óptico que se comunica com uma APD (dispositivo fotodiodo avalanche) responsável pela aquisição das imagens, com um espectrômetro dedicado à obtenção dos espectros Raman. O sistema ficou funcional no que diz respeito a capacidade de executar medidas confocal e está pronto para a realização de medidas de campo próximo.

Ce travail de thèse à été financé par le projet LICORVE (Développement de garnitures légères, innovantes, recyclables et poly-sensorielles pour les applications de coffres de véhicule). Il consiste à développer une méthodologie de mesure pour localiser et caractériser les sources de bruit dans un coffre de voiture. L'environnement de mesure se caractérise par un petit volume où les réflexions de la source d'intérêt et des sources perturbatrices sur les parois ne peuvent être négligées. La méthode doit donc permettre de séparer les différents contributions pour estimer le plus précisément possible les sources étudiées (déconfinement). Dans un premier temps, deux méthodes de séparation : Double Layer SONAH (Statistically Optimal Near el Acoustical Holography) et Field Separation Method (FSM) sont étudiées numériquement. Les limites et avantages de chacune ont été déterminés dans un environnement de mesure confiné. Cela a permis de choisir la méthode la plus adaptée à notre problématique. Dans un deuxième temps les principales conclusions de l'étude numérique sont validées expérimentalement. Dans ce cadre, un ensemble de mesures sont réalisées dans une maquette avec la méthode FSM pour localiser et caractériser des sources maitrisées. Après avoir validée la fiabilité de la méthode de séparation, FSM a été mise en œuvre dans le coffre d'une Peugeot 508 sw en condition de roulement. Les résultats obtenus ont permis d'orienter le choix des garnitures pour un traitement acoustique optimal. / This thesis consists in developing, through the LICORVE project (light garnitures, innovative, recyclable and multi-sensorial for vehicle boots applications), a measurement method for localizing and characterizing noise sources in a vehicle trunk. The measuring environment is distinguished by a small volume where the reflections on the partitions generated by the source of interest and the interfering sources cannot be neglected. Therefore, the method must allow the separation of the different contributions in order to assess accurately the studied sources. As a first step, two separation methods : Double Layer SONAH (Statistically Optimized Near-Field Acoustical Holography) and Field Separation Method (FSM) are numerically studied. The limitations and advantages of each of them are determined in a confined measuring environment; this allowed to select the most appropriate method to tackle our problem. As a second step, the main conclusions of the numerical study are confirmed experimentally. In this context, measurements are performed, using the FSM method, in a trunk mock-up to localize and characterize the controlled sources. So confirmed the reliability of the separation method, it has been tested in the boot of a Peugeot 508 SW on a roller bench. The obtained results allowed guiding the selection of garniture for the acoustic treatment.