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This thesis describes the development of active terahertz modulators based on arrays of coupled resonators loaded with monolayer graphene. The structures affect the amplitude, phase, and polarisation of the transmitted and reflected radiation. These devices were simulated using finite element modelling (FEM) software, fabricated using standard cleanroom lithographic techniques and characterised using terahertz (THz) time-domain spectroscopy (TDS). Devices designed to modulate the phase and frequency of the transmitted and reflected THz radiation were fabricated and characterised operating at ∼ 1.5 THz and 3 THz. Both the 3 THz and 1.5 THz devices were coupled with THz quantum cascade lasers (QCLs). The phase modulators were integrated with a partially suppressed QCL to form an external cavity. The devices acted as optoelectronic mirrors. By changing the bias on the device, the reflected phase changed the effective length of the cavity and affected the mode competition within the laser. The same experiment was also conducted with a gold mirror on a micrometre stage, and the position was changed to vary the external cavity length. They produced commensurate results. These results were compared with simulations of the external cavity and QCL set-up using reduced rate equations, which showed good agreement. Different devices that use coupled bright and dark resonators with capacitative coupling and some that use a double layer of resonators and magnetic coupling were simulated and fabricated. They were designed to change the polarisation of a linear THz beam, changing either the angle of rotation of the linear polarisation or converting from linear to elliptical polarisation, depending on the frequency. These devices were then coupled with THz QCLs to manipulate the linear polarisation output. For further improvement and optimisation of active metasurface devices, we need to understand the behaviour of the individual elements in response to THz incident illumination and their interaction with each other, which is not possible with FEM software. In response, metasurface devices were investigated with room temperature aperture and scattering scanning near-field optical microscopes (SNOM), which can provide subwavelength resolution. Furthermore, they showed the bonding and anti-bonding modes of the sub-wavelength features. For future direct integration of metasurfaces with the QCL facet inside the cryostat, the development of a scattering SNOM (s-SNOM) operating at cryogenic temperatures (∼10 K) was started. However, this proved to have multiple unforeseen difficulties, and much work was undertaken to reduce the vibration so that topography could be taken and so that it functioned as a cryogenic atomic force microscope (AFM)., EPSRC Studentship and EPSRC HyperTHz

The main object of this study will be based on producing and characterization of lithographic thin–film structures produced based electrochromic materials. Atomic force microscopy will be used as a main method of evaluation the morphology of lithographic structures. The optical properties of eslectrochromic materials will be analyze using scanning near–field optical microscopy by applying different electrical potential.

Basic and translational research in reproductive medicine can provide new insights with the application of scanning probe microscopies, such as atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). These microscopies, which provide images with spatial resolution well beyond the optical resolution limit, enable users to achieve detailed descriptions of cell topography, inner cellular structure organization, and arrangements of single or cluster membrane proteins. A peculiar characteristic of AFM operating in force spectroscopy mode is its inherent ability to measure the interaction forces between single proteins or cells, and to quantify the mechanical properties (i.e., elasticity, viscoelasticity, and viscosity) of cells and tissues. The knowledge of the cell ultrastructure, the macromolecule organization, the protein dynamics, the investigation of biological interaction forces, and the quantification of biomechanical features can be essential clues for identifying the molecular mechanisms that govern responses in living cells. This review highlights the main findings achieved by the use of AFM and SNOM in assisted reproductive research, such as the description of gamete morphology; the quantification of mechanical properties of gametes; the role of forces in embryo development; the significance of investigating single-molecule interaction forces; the characterization of disorders of the reproductive system; and the visualization of molecular organization. New perspectives of analysis opened up by applying these techniques and the translational impacts on reproductive medicine are discussed.

We study the effect of Coulomb correlation on the emission properties of the ground state exciton in zincblende CdSe/ZnS core–shell and in wurtzite ZnO quantum dots (QDs). We validate our theory model by comparing results of computed exciton energies of CdSe/ZnS QDs to photoluminescence and scanning near-field optical microscopy measurements. We use that to estimate the diameter of the QDs using a simple model based on infinitely deep quantum well and compare the results with the statistics of the atomic force microscopy scans of CdSe/ZnS dots, obtaining excellent agreement. Thereafter, we compute the energy fine structure of exciton, finding striking difference between properties of zincblende CdSe/ZnS and wurtzite ZnO dots. While in the former the fine structure is dominated by the dipole terms of the multipole expansion of the exchange interaction, in the latter system that is mostly influenced by Coulomb correlation. Furthermore, the correlation sizeably influences also the exciton binding energy and emission radiative rate in ZnO dots.

In 2004 Ohtomo and Hwang discovered that the interface between two band insulators, LaAlO3 and SrTiO3, is conducting. This thesis focuses on the properties of the LaAlO3/SrTiO3 interface at the nanoscale. First, we developed a technique to realize conducting wires of nanometric scale in insulating LaAlO3/SrTiO3 interfaces. Then, we investigated the use of an optical technique with nanometric resolution to study the electronic properties of the interface. Finally, we analyzed the electronic transport in conducting nano-devices. This study yields insights on the complementary effect of low-dimension physics and transition metal metal oxides properties. Moreover, a small portion of this work has been dedicated to the study of spintronic effects stemming from the interplay between spin and charge degrees of freedom at the LaAlO3 /SrTiO3 interface.

In this work we made a review of how a multi-probes microscope using Atomic Force and Near Field Scanning Microscopy works. Currently, the Nanonics Multiview 4000 instaled at the Materials Caracterization and Microscopy Laboratory (LCMMAT) is not completly working. Nowadays, we are able to do Atomic Force Microscopy (AFM) and reflection and transmission Scanning Near Field Microscopy (SNOM) measurements. This kind of microscope have three probes which are able to do simultaneaous mesurements of AFM, C-AFM, SNOM, Raman Microscopy and nanolitography. It is the first multi-probe microscope to be instaled in Latin America. This work consists in studying the structure of this kind of microscope, how does it make AFM and SNOM measurements and how to analise them. We study the different electronic circuits which are used in this kind of microscopes and we compare both optical and tuning-fork feedback. It was explain step by step how to do and AFM and SNOM measurement. We study the processing and analise of this measurements. Finally, we made some different measurements using this tecniques. Some of this measurements were compared with that found in references in order to try to find some possible aplications which could be useful for future researches at our laboratory. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Neste trabalho realizamos uma revisão do funcionamento do Microscópio Raman Confocal Multipontas com Campo Próximo e Força Atômica modelo Multiview 4000 da empresa Nanonics. Atualmente, o microscópio Multiview 4000 do Laboratório de Caracterização e Microscopia de Materiais (LCMMAT) ainda não se encontra operando aos 100%. Ele encontra-se em fase de montagem, estando disponível hoje em dia para uso só o Microscópio de Força Atômica (AFM) e o Microscópio de Campo Próximo (SNOM) nos modos reflexão e transmissão. Este modelo de microscópio, o qual possui três ponteiras que são capazes de fazer medidas em simultâneo de AFM, C-AFM, SNOM e microscopia Raman Confocal, alem de poder fazer nanolitografia, é o primeiro a ser instalado na America Latina. Durante a realização do presente trabalho, estudamos a estrutura do microscópio, como ele realiza as medidas destas duas técnicas e como elas são feitas. No estudo estrutural do Microscópio foram descritos os princípios físicos que são usados para a formação da imagem, alem dos diferentes tipos de circuitos eletrônicos usados em equipamentos de este tipo. Explicou-se passo a passo como são feitas as medidas de AFM e de SNOM. Estudamos também como é feito o analise e o processamento das imagens. Finalmente foram mostradas algumas imagens que foram feitas usando o microscópio, e comparou-se com alguns resultados encontrados na bibliografia a fim de encontrar possíveis aplicações de cada uma das amostras aqui mostradas.

Despite the presence of high performance apparatus such as electronic and near-field microscopes, the capacity to measure nanoscale dimensions with uncertainties down to some nanometers constitutes a real technological obstacle for the mass production of millimeter scale components with nanoscale characteristics. The work realized during this thesis is intended to control at the nanoscale level, over a range of some millimeters, the position of a sample-holder, mainly aimed to microscopy. The system comprises a mechanical translation stage, an interferometric position measurement, high-frequency electronics, and a closed loop control. The displacement system has a dual stage actuator architecture where the first stage is a long-range translation stage, and the second is a piezoelectric actuator allowing rectifying the positioning errors of the first stage. The system allows millimeter range displacements in the X-Y plane with a resolution and repeatability at the nanoscale level. The device was integrated into an atomic force microscope and a scanning near-field optical microscope in order to obtain, at the same time, millimeter-sized and highly resolved images. Topographic and near-field optical images with length higher than 1 mm have been realized in order to show the performances of the system.; Malgré la présence d'appareils très performants tels que les microscopes électroniques et en champ proche, les capacités à mesurer des dimensions nanométriques avec des incertitudes de quelques nanomètres constitue un véritable verrou technologique pour la fabrication en grand volume de composants de taille millimétrique mais aux caractéristiques nanométriques. Les travaux réalisés au cours de cette thèse ont pour but de contrôler avec des performances nanométriques, sur une plage de quelques millimètres, le positionnement d'un porte-échantillon, essentiellement dédié à la microscopie. Le système comprend des platines de déplacement mécanique, une mesure par interférométrie, une électronique haute-fréquence et des lois de commandes pour l'asservissement. Le système de déplacement est constitué de deux étages ; le premier est une platine de translation qui permet de faire des " longues distances ", et le second est un actionneur piézoélectrique qui permet de corriger les défauts du premier. Le système ainsi réalisé permet des déplacements dans les deux directions du plan X-Y avec des résolutions et des répétabilités de l'ordre du nanomètre. Ce dispositif a été intégré à un microscope à force atomique et à un microscope optique en champ proche dans le but de réaliser des images de tailles millimétriques et en même temps hautement résolues. Des images de topographie et des images optiques en champ proche de tailles supérieures à 1 mm de long viennent démontrer les performances du système.

Despite the presence of high performance apparatus such as electronic and near-field microscopes, the capacity to measure nanoscale dimensions with uncertainties down to some nanometers constitutes a real technological obstacle for the mass production of millimeter scale components with nanoscale characteristics. The work realized during this thesis is intended to control at the nanoscale level, over a range of some millimeters, the position of a sample-holder, mainly aimed to microscopy. The system comprises a mechanical translation stage, an interferometric position measurement, high-frequency electronics, and a closed loop control. The displacement system has a dual stage actuator architecture where the first stage is a long-range translation stage, and the second is a piezoelectric actuator allowing rectifying the positioning errors of the first stage. The system allows millimeter range displacements in the X-Y plane with a resolution and repeatability at the nanoscale level. The device was integrated into an atomic force microscope and a scanning near-field optical microscope in order to obtain, at the same time, millimeter-sized and highly resolved images. Topographic and near-field optical images with length higher than 1 mm have been realized in order to show the performances of the system., Malgré la présence d'appareils très performants tels que les microscopes électroniques et en champ proche, les capacités à mesurer des dimensions nanométriques avec des incertitudes de quelques nanomètres constitue un véritable verrou technologique pour la fabrication en grand volume de composants de taille millimétrique mais aux caractéristiques nanométriques. Les travaux réalisés au cours de cette thèse ont pour but de contrôler avec des performances nanométriques, sur une plage de quelques millimètres, le positionnement d'un porte-échantillon, essentiellement dédié à la microscopie. Le système comprend des platines de déplacement mécanique, une mesure par interférométrie, une électronique haute-fréquence et des lois de commandes pour l'asservissement. Le système de déplacement est constitué de deux étages ; le premier est une platine de translation qui permet de faire des " longues distances ", et le second est un actionneur piézoélectrique qui permet de corriger les défauts du premier. Le système ainsi réalisé permet des déplacements dans les deux directions du plan X-Y avec des résolutions et des répétabilités de l'ordre du nanomètre. Ce dispositif a été intégré à un microscope à force atomique et à un microscope optique en champ proche dans le but de réaliser des images de tailles millimétriques et en même temps hautement résolues. Des images de topographie et des images optiques en champ proche de tailles supérieures à 1 mm de long viennent démontrer les performances du système.

My project is concerned with the development of an infrared apertureless scanning near-eld optical microscope (SNOM) that will use the synchrotron radiation of the ESRF as source of infrared light. This radiation has two main particularities well-suited to spectroscopic studies: this is a white source of light covering the near infrared band from 5 to 15 microns where tunable laser sources are still under development and it is very bright and stable, both in time and space. Once developed, the microscope will be applied to the infrared spectroscopy - essentially vibrational - and diagnosis of materials and of local nanostructures which are of current interest to the micro and nanoelectronic industry. As my project is very instrumental, the beginning was dedicated to the conception of a microscope system, starting with nothing and having all the needed materials at the end of the rst year. The second year was dedicated to the integration and implementation of the experimental setup, to the understanding of its functionalities and to trials for validating the new tool. Afterwards we were fully committed to researching and understanding this unique tool. We have started with some preliminary results and then it would essentially be a question of allocated experimental time until obtaining the results that we had aimed for. Our setup is unique and therefore the works we have for reference are from groups using the same techniques operating under very dierent conditions [WFA03; FWA05a; FWLA04; RGEH05; Hil04; GAS+00b; Suk04; TKH04] Our main diffculty is in detecting a weak signal, which we had expected to succeed. I will show later some calculations that made us believe so. One of our reference groups managed to do it in simpler conditions than ours, but it is worth recalling that it took them 3 years to adjust their setup sensitivity, thereby conrming that these are very hard techniques. Our starting idea was of using synchrotron radiation as illuminating source in the infrared range because of its characteristics. This is a white light source, with all the wavelengths present at the same time, allowing us to perform spectroscopy, meaning that we will obtain chemical information of the sample. This is the big novelty comparing with the other works. It turned out that the light is rather weak which makes the search for the signal a diffcult task. Our setup should then be tested with a laser, which is several orders of magnitude more powerful than the synchrotron radiation, and what might be a good debugging tool. This seems a good alternative to better understand what are the critical points that must be improved in our system. The lasers to use could be visible, infrared (CO2), or tunable. For spectroscopy, the tunable lasers are not only less stable but they are also more restricted in the spectral range to the very near infrared part of the spectrum than the synchrotron radiation. The ESRF synchrotron facility is my home lab, and I have worked in collaboration with the CEA-LETI for the development of this tool.; Mon projet porte sur l'elaboration d'un microscope optique en champ proche (SNOM) sans ouverture fonctionnant dans le domaine de l'infrarouge et utilisant le rayonnement synchrotron de l'ESRF comme source de lumiere infrarouge. Ce rayonnement a deux particularites bien adaptees aux etudes spectroscopiques: c'est une source de lumiere blanche couvrant la bande du proche infrarouge de 5 a 15 microns alors que les sources lasers accordables sont encore en developpement. Il est tres brillant et stable, a la fois dans le temps et dans l'espace. Une fois elaboree, le microscope sera appliquee a la spectroscopie infrarouge - essentiellement vibrationelle - et le diagnostic des materiaux et des nanostructures qui sont d'inter^et actuel pour l'industrie micro et nanoelectronique [RCB+02]. Comme mon projet est tres instrumental, le debut a ete consacre a la conception de tout un systeme de microscopie, a partir du zero et avec tout le materiel necessaire disponible a la n de la premiere annee. La seconde annee a ete consacree a l'integration et la mise en oeuvre du dispositif experimental, a la comprehension de ses fonctionnalites et a des essais de validation du nouveau outil. Apres nous nous sommes pleinement engages dans la recherche et la comprehension de cet outil unique. Nous avons commence par quelques resultats preliminaires, puis cela a ete essentiellement une question de temps experimental alloue pour obtenir les resultats que nous avions vises. Notre conguration est unique et donc les travaux que nous avons pour reference sont ceux de groupes utilisant les m^emes techniques d'exploitation dans des conditions tres dierentes. Notre principale diculte est de detecter un signal faible. Je montrerai plus loin quelques calculs qui nous y ont fait croire. Notre groupe de reference a reussi a le faire dans des conditions plus simples que les notres, mais il est utile de rappeler que cela leur a pris 3 ans pour adapter leur sensibilite a l'installation, ce qui conrme que ce sont des techniques tres dur. Notre idee de depart etait d'utiliser le rayonnement synchrotron comme source de lumiere dans l'infrarouge en raison de ses caracteristiques. Il s'agit d'une source de lumiere blanche, avec toutes les longueurs d'onde presentes en meme temps, nous permettant d'eectuer une spectroscopie, ce qui signie que nous obtiendrons une information chimique sur l'echantillon [Hil04; MGCS04]. Telle est la grande nouveaute en comparison avec les autres travaux. Il s'est avere que la lumiere est assez faible ce qui rend la recherche du signal dicile. Notre installation doit alors etre testee avec un laser, qui est de plusieurs ordres de grandeur plus puissant que le rayonnement synchrotron, et qui pourrait etre un bon outil de debogage. Cela semble une bonne alternative pour mieux comprendre les points essentiels qui doivent etre ameliores dans notre systeme. Les lasers a utiliser pourraient etre visible, infrarouge (CO2), ou accordable. Pour la spectroscopie, les lasers accordables sont non seulement moins stables mais ils sont aussi plus limites dans la gamme spectrale sur la partie infrarouge proche du spectre, que le rayonnement synchrotron. Le synchrotron de l'ESRF est mon laboratoire d'accueil, et j'ai travaille en collaboration avec le CEA-LETI pour le developpement de cet outil.

My project is concerned with the development of an infrared apertureless scanning near-eld optical microscope (SNOM) that will use the synchrotron radiation of the ESRF as source of infrared light. This radiation has two main particularities well-suited to spectroscopic studies: this is a white source of light covering the near infrared band from 5 to 15 microns where tunable laser sources are still under development and it is very bright and stable, both in time and space. Once developed, the microscope will be applied to the infrared spectroscopy - essentially vibrational - and diagnosis of materials and of local nanostructures which are of current interest to the micro and nanoelectronic industry. As my project is very instrumental, the beginning was dedicated to the conception of a microscope system, starting with nothing and having all the needed materials at the end of the rst year. The second year was dedicated to the integration and implementation of the experimental setup, to the understanding of its functionalities and to trials for validating the new tool. Afterwards we were fully committed to researching and understanding this unique tool. We have started with some preliminary results and then it would essentially be a question of allocated experimental time until obtaining the results that we had aimed for. Our setup is unique and therefore the works we have for reference are from groups using the same techniques operating under very dierent conditions [WFA03; FWA05a; FWLA04; RGEH05; Hil04; GAS+00b; Suk04; TKH04] Our main diffculty is in detecting a weak signal, which we had expected to succeed. I will show later some calculations that made us believe so. One of our reference groups managed to do it in simpler conditions than ours, but it is worth recalling that it took them 3 years to adjust their setup sensitivity, thereby conrming that these are very hard techniques. Our starting idea was of using synchrotron radiation as illuminating source in the infrared range because of its characteristics. This is a white light source, with all the wavelengths present at the same time, allowing us to perform spectroscopy, meaning that we will obtain chemical information of the sample. This is the big novelty comparing with the other works. It turned out that the light is rather weak which makes the search for the signal a diffcult task. Our setup should then be tested with a laser, which is several orders of magnitude more powerful than the synchrotron radiation, and what might be a good debugging tool. This seems a good alternative to better understand what are the critical points that must be improved in our system. The lasers to use could be visible, infrared (CO2), or tunable. For spectroscopy, the tunable lasers are not only less stable but they are also more restricted in the spectral range to the very near infrared part of the spectrum than the synchrotron radiation. The ESRF synchrotron facility is my home lab, and I have worked in collaboration with the CEA-LETI for the development of this tool., Mon projet porte sur l'elaboration d'un microscope optique en champ proche (SNOM) sans ouverture fonctionnant dans le domaine de l'infrarouge et utilisant le rayonnement synchrotron de l'ESRF comme source de lumiere infrarouge. Ce rayonnement a deux particularites bien adaptees aux etudes spectroscopiques: c'est une source de lumiere blanche couvrant la bande du proche infrarouge de 5 a 15 microns alors que les sources lasers accordables sont encore en developpement. Il est tres brillant et stable, a la fois dans le temps et dans l'espace. Une fois elaboree, le microscope sera appliquee a la spectroscopie infrarouge - essentiellement vibrationelle - et le diagnostic des materiaux et des nanostructures qui sont d'inter^et actuel pour l'industrie micro et nanoelectronique [RCB+02]. Comme mon projet est tres instrumental, le debut a ete consacre a la conception de tout un systeme de microscopie, a partir du zero et avec tout le materiel necessaire disponible a la n de la premiere annee. La seconde annee a ete consacree a l'integration et la mise en oeuvre du dispositif experimental, a la comprehension de ses fonctionnalites et a des essais de validation du nouveau outil. Apres nous nous sommes pleinement engages dans la recherche et la comprehension de cet outil unique. Nous avons commence par quelques resultats preliminaires, puis cela a ete essentiellement une question de temps experimental alloue pour obtenir les resultats que nous avions vises. Notre conguration est unique et donc les travaux que nous avons pour reference sont ceux de groupes utilisant les m^emes techniques d'exploitation dans des conditions tres dierentes. Notre principale diculte est de detecter un signal faible. Je montrerai plus loin quelques calculs qui nous y ont fait croire. Notre groupe de reference a reussi a le faire dans des conditions plus simples que les notres, mais il est utile de rappeler que cela leur a pris 3 ans pour adapter leur sensibilite a l'installation, ce qui conrme que ce sont des techniques tres dur. Notre idee de depart etait d'utiliser le rayonnement synchrotron comme source de lumiere dans l'infrarouge en raison de ses caracteristiques. Il s'agit d'une source de lumiere blanche, avec toutes les longueurs d'onde presentes en meme temps, nous permettant d'eectuer une spectroscopie, ce qui signie que nous obtiendrons une information chimique sur l'echantillon [Hil04; MGCS04]. Telle est la grande nouveaute en comparison avec les autres travaux. Il s'est avere que la lumiere est assez faible ce qui rend la recherche du signal dicile. Notre installation doit alors etre testee avec un laser, qui est de plusieurs ordres de grandeur plus puissant que le rayonnement synchrotron, et qui pourrait etre un bon outil de debogage. Cela semble une bonne alternative pour mieux comprendre les points essentiels qui doivent etre ameliores dans notre systeme. Les lasers a utiliser pourraient etre visible, infrarouge (CO2), ou accordable. Pour la spectroscopie, les lasers accordables sont non seulement moins stables mais ils sont aussi plus limites dans la gamme spectrale sur la partie infrarouge proche du spectre, que le rayonnement synchrotron. Le synchrotron de l'ESRF est mon laboratoire d'accueil, et j'ai travaille en collaboration avec le CEA-LETI pour le developpement de cet outil.

The aim of this thesis was the study of lipid rafts with scanning probe microscopies, particularly SNOM and AFM. Contrarly to earlier views, lipids do not mix homogeneously in membranes but form domains and micro-domains of different sizes. Glycolipids, such as ganglioside GM1, are receptors for numerous biologically active agents and are likely to be involved in the formation of specialized micro-domains, called «rafts». Characterization of these domains is essential to understand their role in membrane processes. Determination, at the mesoscopic scale, of raft distribution in synthetic and natural membranes has been studied by various techniques and has led to conflicting results: the size of rafts is postulated to be far beyond the resolution of conventional optical microscopy. Langmuir Blodgett films are useful membrane models and are prepared with lipid mixture as a mimic for the natural rafts found in membranes. The characterization of the structure of LB films with SNOM and AFM offers the possibility of obtaining topographic and optical information ranging from nanometer to micrometer resolution.The first project, L'objectif des travaux présentés dans cette thèse est l'étude des rafts lipidique au moyen des microscopes à sonde locale, notamment le SNOM et l'AFM. Contrairement aux premières observations les lipides ne se mélangent pas de façon homogène dans les membranes mais forment des domaines et micro-domaines de tailles différentes. Les glycolipides, tels que les gangliosides G[indice]M1, sont les récepteurs de nombreux agents biologiques et sont impliqués dans la formation de micro-domaines spécialisés, appelés rafts. La caractérisation de tels domaines est essentielle pour comprendre leur rôle dans les processus membranaires. La détermination à l'échelle mésoscopique, de la distribution des rafts dans des membranes naturelles et synthétiques, a été étudiée avec différentes techniques et a conduit à des résultats contradictoires: la taille des rafts est postulée comme étant loin de la résolution des microscopes classiques. Notre modèle membranaire repose sur des films de Langmuir préparés avec des mélanges de lipides afin d'imiter la composition des rafts trouvés dans les membranes; la caractérisation de leurs structures avec le SNOM et l'AFM offre lac possibilité d'obtenir des informations optiques et topographiques allant du nanomètre au micromètre. Le premier volet de ce travail portait sur le développement et la fabrication de nano-sondes courbées pour le SNOM. Ces nano-sondes sont hautement spécifiques et présentent les caractéristiques suivantes: facteur de transmission élevé proche de 10[exposant]-2 pour un diamètre de 100 nm, seuil de destruction élevé et faible constante de raideur pour balayer les échantillons mous. Les images AFM et fluorescence en SNOM montrent que les gangliosides forment,de minuscules domaines et filaments qui sont distribués de façon hétérogène, dans la phase lipidique la plus ordonnée. Finalement, grâce aux techniques complémentaires du SNOM ,et de l' AFM, nous montrons que la taille des micro-domaines de G[exposant]M1 est comparable avec celles obtenues dans les membranes naturelles...

In this work we employed Atomic Force Microscopy (AFM) and Scanning Near-field Optical Microscopy (SNOM) techniques to study the effect of the interaction between human keratinocytes (HaCaT) and electromagnetic fields at low frequency. HaCaT cells were exposed to a sinusoidal magnetic field at a density of 50 Hz, 1mT. We performed AFM analysis showed modification in shape and morphology in exposed cells with an increase of the areas of adhesion between cells. This last evidence has been confirmed by SNOM indirect immunofluorescence analysis performed with a fluorescent antibody against the adhesion marker b4 integrin, which revealed an increase of b4 integrin segregation in the cell membrane of 50 Hz exposed cells, suggesting that a higher percentage of these cells shows a modified pattern of this adhesion marker

Carbon nanotubes the long, cylindrical carbon molecules are the most exciting material discovered lately. They offer the possibility for a large number of applications. My task was to explore the way how we can use multi-walled carbon nanotubes (MWNT) in scanning probe applications: Atomic Force Microscopy (AFM) and Scanning Nearfield Optical Microscopy (SNOM). Carbon nanotubes (CNTs) are potentially ideal atomic force microscopy probes because they can have diameters as small as one nanometer, they have robust mechanical properties, and can be specifically functionalized with chemical and biological probes at the tip ends. CNTs will not wear, because they buckle elastically under applied load and thus will stay sharp. They also show exceptional field emission properties, and remarkably enough, the field emission at high currents is accompanied by light emission. This phenomenon offers the possibility to use CNTs as nanometer-size light sources for SNOM. In order to test CNTs for AFM and SNOM applications a mounting method has been elaborated. Two nanomanipulators have been designed and constructed for operations inside a Transmission and Scanning Electron Microscopes (TEM and SEM). This latter one with large work space and available electrical contacts allowed versatile use of nanomanipulator, including in situ field emission, and photon counting measurements using a photodiode. Hundreds of individual MWNT and double-wall nanotubes (DWNT) bundles, produced by arc-discharge (AD) or chemical vapour deposition (CVD) method, have been mounted, one-by-one, on either commercial AFM probes or sharpened metallic wires (W, Au, Pt). The tests show that in both case, AFM and SNOM probes, the weakest point is the attachment of the nanotube to the support. Amorphous carbon deposit is good for attaching nanotubes for limited time and limited applications, but it deforms under the forces that it has been submitted to during AFM scans. This weak bonding of nanotubes is the source of failure in AFM. In field/light emission the high contact resistance, which can change during the mechanical stress exerted by the applied electric field, will lead to a Joule heating of the nanotube/contact area and results a thermal breakdown of the tip. Attempts were made to elaborate a good mechanical and electrical attachment of the carbon nanotubes to the Si/metallic cantilever by using indium as bonding agent.