This thesis discusses the design and construction of a Near-field Scanning Optical Microscope (NSOM). Basic principles of operation, the characteristics of the hardware components, and the control software are discussed. A unique method of controlling the position of the probe is developed, and scans of a diffraction grating are presented. We show the influence that the surface topology and reflectivity and the interference of direct and reflected light have on the images. A second design of the instrument, for use in a vacuum chamber and with a flexure stage for lateral motion, is accomplished. / text

O microscópio é um instrumento de grande relevância para o contexto científico. Dentre as variadas montagens desse instrumento óptico, os microscópios sem lentes têm chamado atenção por serem robustos, reduzidos em tamanho e custo, e ainda possibilitarem imagens com amplo campo de visão (usualmente da ordem de algumas dezenas de mm2). Dentro dessa categoria, existem os microscópios holográficos in-line, os quais obtêm a imagem da amostra a partir da reconstrução numérica de um holograma adquirido por um sensor digital de imagem. Este trabalho tem o objetivo de construir um desses microscópios para observar amostras semitransparentes. O microscópio desenvolvido ao longo deste trabalho tem sua iluminação baseada no uso de um LED associado a um pinhole, cuja finalidade é aumentar a coerência temporal da luz. Com isso, a iluminação proveniente do pinhole percorre uma distância de aproximadamente 10 cm até atingir a amostra, posicionada sobre uma lâmina de vidro. À uma distância mínima da amostra, está posicionado um sensor CMOS, responsável pela aquisição do padrão de interferência da parcela da luz que foi transmitida sem desvio pela amostra e da parte da luz que foi difratada por ela. Esse padrão de intensidade, chamado holograma, é reconstruído numericamente de modo a obter uma boa imagem do objeto-alvo. A reconstrução da imagem medida é feita considerando a propagação da luz de volta ao plano de do objeto e, depois, estimando a fase referente à luz incidente no sensor no instante da medida. Essa primeira etapa resulta na imagem da amostra com a influência de um artefato muito conhecido na holografia: a imagem gêmea. Enquanto a reconstrução de fase reconstrói a imagem de uma forma mais completa, reduzindo a influência de tais artefatos. A reconstrução de fase é feita com o método multialturas, o qual faz uso de mais de uma imagem medida, com distâncias diferentes entre a amostra e o sensor, como entrada para o algoritmo desenvolvido. Utilizando um sensor de 10 MP (3856 x 2764 pixels), com o pixel de 1,67 μm, construímos um microscópio holográfico sem lentes com um campo de visão de quase 30 mm2 e resolução de aproximadamente 3 μm. / The microscope is an instrument of great relevance in the scientific context. Among various assembly of this optic instrument, the lensless microscope have had drawing attention by been robust, with small size and low cost and, in addiction, enable imaging with a large field of view (usually about tens of mm2). Inside this category, there is the in-line holographic microscopes, which achieve the sample image from the numerical reconstruction of a hologram acquired by an image digital sensor. This study have the objective of develop one of these microscopes to image semitransparent samples. The microscope developed over this study has its illumination based on the use of an LED associated with a pinhole, whose purpose is to increase the light temporal coherence. Therefore, illumination from the pinhole goes 10 cm until reach the sample, positioned over the glass slide. From a minimal distance of the sample, a CMOS sensor is positioned, which is responsible to acquire the interference pattern of the transmitted light with the diffracted light. This intensity pattern, called hologram, is numerically reconstructed in order to get a great image of target object. The reconstruction of the measured image is performed considering the back propagation of the light to the object plane and, then, estimating the phase related to the incident light over the sensor at the time of the measurement. This first step results in a sample image influenced by an artifact well-known in the holography: the twin-image. Whereas phase reconstruction reconstruct the image more fully, reducing the artifact influence. Phase reconstruction is performed using the multiheigh method, which uses more than one measured image, with different distances between the sample and sensor, as input to the developed algorithm. Using a 10 MP (3856 x 2764 pixels) sensor, with a pixel size of 1.67 μm, we built a lensless holographic microscope with a field of view near of 30 mm2 and resolution of approximately 3 μm.

Laser nano-patterning with near-field optical microscope (NSOM) and the associated energy transport analysis are achieved in this study. Based on combined experimental/theoretical analyses, it is found that laser nano-patterning with a NSOM probes strongly depend on the laser conditions and material properties of the target: the energy transport from the NSOM probes to the targets changes from pure optical to a combination of thermal and optical transport when the pulse duration of laser is increased from femtosecond to nanosecond. As a result, the mechanisms of nano-pattern formation on targets changes from nano-ablation to nano-oxidation/ recrystallization when the laser pulse duration is increased from femtosecond to nanosecond. Also, with the laser nano-patterning experiments, thermal damage of NSOM probes is observed which can be attributed to the low transport efficiency (10-4 – 10-6) and associated heating of the metal cladding of NSOM probes. The heating of NSOM probes are studied with developed time harmonic and transient thermoreflectance (TR) imaging. From time harmonic TR when the NSOM probes are driven with continuous laser, it is found that the location of heating of NSOM probes is ~20-30µm away from the NSOM tip. The strength of the heating is determined by the laser power (linear dependence), wavelength of the laser (stronger with short A), and aperture size of NSOM probes (stronger when aperture size < A/2). From the transient TR imaging when the NSOM probes are driven with pulsed laser, it is found that the peak temperature of the NSOM probe shifts much closer to the tip. The possible reason for the change in the location of peak temperature when continuous laser is changed to pulsed laser can be attributed to the competition between the heat generation and dissipation rates at different location of the probe: the tip experiences highest temperature with pulsed heating as the entire heating processes is adiabatic. The tip also experiences highest heat dissipation rate due to its large surface-to-volume ratio which overcomes the heat generation at the tip under quasi-steady state resulting in shift of the hot spot. The knowledge obtained in this study can be important in the future design of more efficient NSOM probes and other nano-optic devices.

O microscópio é um instrumento de grande relevância para o contexto científico. Dentre as variadas montagens desse instrumento óptico, os microscópios sem lentes têm chamado atenção por serem robustos, reduzidos em tamanho e custo, e ainda possibilitarem imagens com amplo campo de visão (usualmente da ordem de algumas dezenas de mm2). Dentro dessa categoria, existem os microscópios holográficos in-line, os quais obtêm a imagem da amostra a partir da reconstrução numérica de um holograma adquirido por um sensor digital de imagem. Este trabalho tem o objetivo de construir um desses microscópios para observar amostras semitransparentes. O microscópio desenvolvido ao longo deste trabalho tem sua iluminação baseada no uso de um LED associado a um pinhole, cuja finalidade é aumentar a coerência temporal da luz. Com isso, a iluminação proveniente do pinhole percorre uma distância de aproximadamente 10 cm até atingir a amostra, posicionada sobre uma lâmina de vidro. À uma distância mínima da amostra, está posicionado um sensor CMOS, responsável pela aquisição do padrão de interferência da parcela da luz que foi transmitida sem desvio pela amostra e da parte da luz que foi difratada por ela. Esse padrão de intensidade, chamado holograma, é reconstruído numericamente de modo a obter uma boa imagem do objeto-alvo. A reconstrução da imagem medida é feita considerando a propagação da luz de volta ao plano de do objeto e, depois, estimando a fase referente à luz incidente no sensor no instante da medida. Essa primeira etapa resulta na imagem da amostra com a influência de um artefato muito conhecido na holografia: a imagem gêmea. Enquanto a reconstrução de fase reconstrói a imagem de uma forma mais completa, reduzindo a influência de tais artefatos. A reconstrução de fase é feita com o método multialturas, o qual faz uso de mais de uma imagem medida, com distâncias diferentes entre a amostra e o sensor, como entrada para o algoritmo desenvolvido. Utilizando um sensor de 10 MP (3856 x 2764 pixels), com o pixel de 1,67 &mu;m, construímos um microscópio holográfico sem lentes com um campo de visão de quase 30 mm2 e resolução de aproximadamente 3 &mu;m. / The microscope is an instrument of great relevance in the scientific context. Among various assembly of this optic instrument, the lensless microscope have had drawing attention by been robust, with small size and low cost and, in addiction, enable imaging with a large field of view (usually about tens of mm2). Inside this category, there is the in-line holographic microscopes, which achieve the sample image from the numerical reconstruction of a hologram acquired by an image digital sensor. This study have the objective of develop one of these microscopes to image semitransparent samples. The microscope developed over this study has its illumination based on the use of an LED associated with a pinhole, whose purpose is to increase the light temporal coherence. Therefore, illumination from the pinhole goes 10 cm until reach the sample, positioned over the glass slide. From a minimal distance of the sample, a CMOS sensor is positioned, which is responsible to acquire the interference pattern of the transmitted light with the diffracted light. This intensity pattern, called hologram, is numerically reconstructed in order to get a great image of target object. The reconstruction of the measured image is performed considering the back propagation of the light to the object plane and, then, estimating the phase related to the incident light over the sensor at the time of the measurement. This first step results in a sample image influenced by an artifact well-known in the holography: the twin-image. Whereas phase reconstruction reconstruct the image more fully, reducing the artifact influence. Phase reconstruction is performed using the multiheigh method, which uses more than one measured image, with different distances between the sample and sensor, as input to the developed algorithm. Using a 10 MP (3856 x 2764 pixels) sensor, with a pixel size of 1.67 &mu;m, we built a lensless holographic microscope with a field of view near of 30 mm2 and resolution of approximately 3 &mu;m.

This master’s thesis deals with the construction design of microscope episcopic LED illumination source and subsequent functional sample realization. Illumination source is compatible with industrial microscope Nikon Eclipse LV150 and designed as a replacement for halogen light source. Way of collecting light is chosen with respect to search analysis results and collector optical element and LED is selected with respect to the analysis of the episcopic illuminator. Two construction designs are designed with respect to the results of photometric analyzes. Optimal design is realized and compared with used lighting sources – halogen and xenon.

Les nanocristaux semi-conducteurs colloïdaux possèdent des propriétés photo-physiques qui en font des objets de choix pour des applications variées, comme le marquage biologique, le photovoltaïque ou encore l’optique quantique. Leur interaction avec une structure photonique peut modifier leurs propriétés d’émission (durée de vie, intensité…). Le microscope optique de champ proche est un outil privilégié pour venir sonder ces modifications à l’échelle nanométrique.Cette thèse porte sur la réalisation d’une sonde active de champ proche réalisée à partir d’un nanocristal cœur/coquille CdSe/CdS greffé à l’apex d’une fibre optique amincie. Cette sonde est utilisée pour cartographier, dans les 3 dimensions de l’espace et à l’échelle nanométrique, les variations de durée de vie de l’émetteur. Elle permet de rendre compte des variations des modes photoniques sur la surface.Une partie de cette thèse porte sur la réalisation de la sonde active elle-même. Grâce à cette sonde les études sont alors développées sur un réseau de trous dans un film mince d’or. Des simulations FDTD ont été réalisées dans le but de déterminer les paramètres pertinents du réseau et d’analyser leur réponse en champ proche.Les résultats expérimentaux des durées de vie en divers points de différents réseaux, obtenus avec la sonde active, sont confrontés aux résultats numériques. / Colloidal semiconductor nanocrystals have photo-physical properties that make them objects of choice for various applications, such as biological marking, photovoltaics or quantum optics. Their interaction with a photonic structure can modify their emission properties (lifetime, intensity, etc.). The near-field optical microscope is a privileged tool to probe these changes at the nanoscale.This thesis deals with the realization of an active near-field probe made from a CdSe / CdS core / shell nanocrystal grafted to the apex of a thinned optical fiber. This probe is used to map, in the 3 dimensions of the space and on the nanometric scale, the variations in the lifetime of the emitter. It makes it possible to account for variations in photonic modes on the surface.A part of this thesis concerns the realization of the active probe itself. Thanks to this probe the studies are then developed on a hole grating made in a thin film of gold. FDTD simulations were performed to determine relevant grating parameters and to analyze their near field response.The experimental results of the lifetimes at various points of different gratings, obtained with the active probe, are compared with the numerical results.

No / Noncontact scanning near-field optical microscope (SNOM) systems can be used to optically resolve samples in atmospheric conditions at theoretical resolutions comparable to those of transmission electron microscope and atomic force microscope systems. SNOM systems are also increasingly used to image biological samples. In this study we custom built a SNOM system with the aim of further demonstrating the potential applications of near-field optical examination of biological material. In this study we were able to image both fixed whole-cell samples in air and liquid environments and live whole-cell samples in liquids. The images acquired were of a relatively low resolution, but this work has shown that SNOM systems can be used to monitor the dynamics of living cells at subnanometric resolutions in the z axis and for fluorescent imaging of whole cells in a liquid medium.

A series of pottery samples provided from the survey investigations and excavations from Degirmentepe Mound (Malatya), belonging to Chalcolithic (Ubaid), Early Bronze and Iron Ages, were investigated by petrographic and X-ray diffraction (XRD) analyses to determine their textures, mineralogical compositions and microstructures. The sample microstructures and chemical (semiquantitative) compositions were also studied by scanning electron microscope with energy dispersive X-ray spectrometry (SEM - EDX). The chemical analyses of some samples were further investigated by inductively coupled plasma &ndash / optical emission spectrometry (ICP-OES). Almost all samples were observed to consist of rock fragments, originating from metamorphic and igneous rocks, although larger grain sizes and higher grain to matrix ratios are recorded for Chalcolithic Age samples compared to those samples belonging to Iron Age. XRD investigations on representative samples of the three periods, revealed high abundances of quartz, feldspar, and pyroxene group minerals in all samples, while the presence of hematite and mica minerals were observed both in Chalcolithic and Iron Age samples, but underlying the use of micaceous raw materials mostly in Iron Age. In the XRD traces of the investigated sherds of Chalcolithic and Iron Ages, the absence of clay fractions both in the bulk and oriented samples, supports a minimum firing temperature of around 800- 850 &deg / C, while the presence of mullite phase both in XRD and SEM &ndash / EDX results showed the possible use of high firing temperatures, in the range of 950&ndash / 1050&deg / C, starting from Chalcolithic Age. Chemical compositions of major oxides obtained ICP &ndash / OES analyses exhibit similar compositions both for Chalcolithic and Iron Age samples. Few exceptions observed may indicate possible use of different raw material and/or different manufacturing technique.

Infrared antennas are employed in sensing applications requiring specific spectral, polarization, and directional properties. Because of their inherently small dimensions, there is significant interaction, both thermal and electromagnetic, between the antenna, the antenna-coupled sensor, and the low-frequency readout structures necessary for signal extraction at the baseband modulation frequency. Validation of design models against measurements requires separation of these effects so that the response of the antenna-coupled sensor alone can be measured in a calibrated manner. Such validations will allow confident extension of design techniques to more complex infrared-antenna configurations. Two general techniques are explored to accomplish this goal. The extraneous signal contributions can be measured separately with calibration structures closely co-located near the devices to be characterized. This approach is demonstrated in two specific embodiments, for removal of cross-polarization effects arising from lead lines in an antenna-coupled infrared dipole, and for removal of distributed thermal effects in an infrared phased-array antenna. The second calibration technique uses scanning near-field microscopy to experimentally determine the spatial dependence of the electric-field distributions on the signal-extraction structures, and to include these measured fields in the computational electromagnetic model of the overall device. This approach is demonstrated for infrared dipole antennas which are connected to coplanar strip lines. Specific situations with open-circuit and short-circuit impedances at the termination of the lines are investigated.

La miniaturisation des pièces est une étape importante pour la progression de la microtechnologie dans plusieurs domaines (connectique, médical, optique, microsystèmes mécaniques). Pour cela, le moulage par microinjection, semble être la solution clé pour la production à grande échelle de micro-composants de polymères. Pour les polymères semi-cristallins, la cristallisation, sous fort taux de cisaillement et sous des vitesses de refroidissement élevées (about 100 K/s), induit des morphologies et des propriétés spécifiques. Elle prend donc une importance considérable dans le processus de microinjection par rapport au moulage par injection classique où les épaisseurs injectées sont généralement supérieures à 1 mm. Ces microstructures ont une grande influence sur les propriétés mécaniques du produit final. La prédiction de ces propriétés à partir de la description de la microstructure est un défi technique et scientifique. Durant cette thèse, deux polymères semi-cristallins ont été microinjectés, le polyéthylène haute densité et le polyamide 12. Les analyses obtenues par la microscopie otiques montrent que les morphologies cristallines varient entre les micro- et les macro-pièces. Tandis que la morphologie de ‘peau-cœur' est présente dans les macropièces, les micropièces présentent une morphologie plutôt particulière. Les analyses combinées de diffusion et de diffraction des rayons X (SAXS et WAXS) avec un microfaisceau synchrotron, nous ont permis de déterminer la microstructure induite par le processus de microinjection dans toute l'épaisseur des pièces. Nous avons constaté que la morphologie et les orientations cristallines induites sont très dépendantes des conditions d'injection ou de microinjection. Une diminution de l'épaisseur, de la vitesse et de la température du moule, augmente l'orientation cristalline en limitant la relaxation des chaînes de polymères. / The components miniaturization is an important step in the evolution of micro technology in several domain (connectivity, medical, optical, mechanical, microsystems). For this purpose, the micro-injection molding seems to be the key solution for the large-scale micro-polymer components production.The crystallization of the semi-crystalline polymers under high shear and cooling rates (about 100 K / s), induces specific properties and morphologies, consequently, it takes a substantial importance in the process of micro-injection compared to conventional injection molding where the usually injected thicknesses is over 1 mm. These micro-structures have a great influence on the mechanical propertie of the final product. The prediction of the final product's properties based on the illustration of the micro-structure is a technical and scientific challenge. In this thesis, two semi-crystalline polymers were micro-injected, the high density polyethylene and the polyamide 12. The obtained analyzes with the use of an optical microscope showed that the Morphology of Crystals vary between micro-and macro-pieces. While the morphology of 'peau-cœur' is present in the macro-pieces, the micro-parts have a particular morphology. The combined analysis of diffusion and X-ray diffraction (WAXS and SAXS) along with the synchrotron microbeam, has allowed us to determined the micro-structure induced by the micro-injection process throughout the thickness of the pieces.We have identified that the morphology and the induced crystal's orientation are very dependent on the conditions of injection or micro-injection. The decrease of the thickness,speed and temperature of the mold will increase the crystal orientation by limiting the relaxation of the polymer chains.