Three new reconstruction methods for quantitative phase imaging, including two interrelated two-dimensional methods, called multifilter phase imaging with partially coherent light and phase optical transfer function recovery, which lead to a third three-dimensional method, called tomographic deconvolution phase microscopy, were developed in response to a growing need among biomedical end users for solutions which can be integrated on standard microscope platforms. The performance of these new methods were evaluated using modelling and simulation as well as experimentation with known test cases. In addition to the development of new methods, existing methods for quantitative phase imaging were applied to characterize the effects of manufacturing, cleaving, and fusion splicing in large-mode-area erbium- and ytterbium-doped optical fibers.

Quantitative phase imaging (QPI) is a category of imaging techniques that can retrieve the phase information of the sample quantitatively. QPI features label-free contrast and non-contact detection. It has thus gained rapidly growing attention in biomedical imaging. Capable of resolving biological specimens at tissue or cell level, QPI has become a powerful tool to reveal the structural, mechanical, physiological and spectroscopic properties. Over the past two decades, QPI has seen a broad spectrum of evolving implementations. However, only a few have seen successful commercialization. The challenges are manifold. A major problem for many QPI techniques is the necessity of a custom-made system which is hard to interface with existing commercial microscopes. For this type of QPI techniques, the cost is high and the integration of different imaging modes requires nontrivial hardware modifications. Another limiting factor is insufficient sensitivity. In QPI, sensitivity characterizes the system repeatability and determines the quantification resolution of the system. With more emerging applications in cell imaging, the requirement for sensitivity also becomes more stringent. In this work, a category of highly sensitive full-field QPI techniques based on wavelength shifting interferometry (WSI) is proposed. On one hand, the full-field implementations, compared to point-scanning, spectral domain QPI techniques, require no mechanical scanning to form a phase image. On the other, WSI has the advantage of preserving the integrity of the interferometer and compatibility with multi-modal imaging requirement. Therefore, the techniques proposed here have the potential to be readily integrated into the ubiquitous lab microscopes and equip them with quantitative imaging functionality. In WSI, the shifts in wavelength can be applied in fine steps, termed swept source digital holographic phase microscopy (SS-DHPM), or a multi-wavelength-band manner, termed low coherence wavelength shifting interferometry (LC-WSI). SS-DHPM brings in an additional capability to perform spectroscopy, whilst the LC-WSI achieves a faster imaging rate which has been demonstrated with live sperm cell imaging. In an attempt to integrate WSI with the existing commercial microscope, we also discuss the possibility of demodulation for low-cost sources and common path implementation. Besides experimentally demonstrating the high sensitivity (limited by only shot noise) with the proposed techniques, a novel sensitivity evaluation framework is also introduced for the first time in QPI. This framework examines the Cramér-Rao bound (CRB), algorithmic sensitivity and experimental sensitivity, and facilitates the diagnosis of algorithm efficiency and system efficiency. The framework can be applied not only to the WSI techniques we proposed, but also to a broad range of QPI techniques. Several popular phase shifting interferometry techniques as well as off-axis interferometry is studied. The comparisons between them are shown to provide insights into algorithm optimization and energy efficiency of sensitivity. / Doctor of Philosophy / The most common imaging systems nowadays capture the image of an object with the irradiance perceived by the camera. Based on the intensity contrast, morphological features, such as edges, humps, and grooves, can be inferred to qualitatively characterize the object. Nevertheless, in scientific measurements and research applications, a quantitative characterization of the object is desired. Quantitative phase imaging (QPI) is such a category of imaging techniques that can retrieve the phase information of the sample by properly design the irradiance capturing scheme and post-process the data, converting them to quantitative metrics such as surface height, material density and so on. The imaging process of QPI will neither harm the sample nor leave exogenous residuals. As a result, it has thus gained rapidly growing attention in biomedical imaging. Over the past two decades, QPI has seen a broad spectrum of evolving implementations, but only a few have seen successful commercialization. The challenges are manifold whilst one stands out - that they have expensive optical setups that are often incompatible with existing commercial microscope platforms. The setups are also very complicated such that without professionals having solid optics background, it is difficult to operate the system to perform imaging applications. Another limiting factor is the insufficient understanding of sensitivity. In QPI, sensitivity characterizes the system repeatability and determines its quantification resolution. With more emerging applications in cell imaging, the requirement for sensitivity also becomes more stringent. In this work, a category of highly sensitive full-field QPI techniques based on wavelength shifting interferometry (WSI) is proposed. WSI images the full-field of the sample simultaneously, unlike some other techniques requiring scanning one probe point across the sample. It also has the advantage of preserving the integrity of the interferometer, which is the key structure to enable highly sensitive measurement for QPI methods. Therefore, the techniques proposed here have the potential to be readily integrated into the ubiquitous lab microscopes and equip them with quantitative imaging functionality. Differed by implementations, two WSI techniques have been proposed, termed swept source digital holographic phase microscopy (SS-DHPM), and low coherence wavelength shifting interferometry (LC-WSI), respectively. SS-DHPM brings in an additional capability to perform spectroscopy, whilst the LC-WSI achieves a faster imaging rate which has been demonstrated with live sperm cell imaging. In an attempt to integrate WSI with the existing commercial microscope, we also discuss the possibility of demodulation for low-cost sources and common path implementation. Besides experimentally demonstrating the high sensitivity with the proposed techniques, a novel sensitivity evaluation framework is also introduced for the first time in QPI. This framework not only examines the realistic sensitivity obtained in experiments, but also compares it to the theoretical values. The framework can be widely applied to a broad range of QPI techniques, providing insights into algorithm optimization and energy efficiency of sensitivity.

Quantitative phase Imaging(QPI) has emerged as a valuable tool for imaging specimens with weak scattering and absorbing abilities such as cells and tissues. It is complementary to fluorescence microscopy, as such, it can be applied to unlabelled specimens without the need for fluorescent tagging. By quantitatively mapping the phase changes induced in the incident light field by the optical path length delays of the specimen, QPI provides objective measurement of the cellular dynamics and enables imaging the specimen with high contrast. Transport of Intensity Equation(TIE) is a powerful computational tool for QPI because of its experimental and computational simplicity. Using TIE, the phase can be quantitatively retrieved from defocused intensity images. However, the resolution of the phase image computed using TIE is limited by the diffraction limit of the imaging system used to capture the intensity images. In this thesis, we have developed a super resolution phase imaging technique by applying the principles of Structured Illumination Microscopy(SIM) to Transport of Intensity phase retrieval. The modulation from the illumination shifts the high frequency components of the phase object into the system pass-band. This enables phase imaging with resolutions exceeding the diffraction limit. The proposed method is experimentally validated using a custom-made upright microscope. Because of its experimental and computational simplicity, the method in this thesis should find application in biomedical laboratories where super resolution phase imaging is required / Master of Science / Transport of Intensity Equation is a quantitative phase microscopy technique that enables imaging thin transparent specimens with high phase contrast using a through focus intensity stack. It provides speckle free imaging, compatibility with bright field microscopes and valid under partial coherence. However, the Optical Transfer Function(OTF) of the imaging system or the microscope acts a low pass filter, effectively limiting the maximum spatial frequency that can pass through the system. This reduces the spatial resolution of the computed phase image to the spatial diffraction limit. There has been a continuous drive to develop Super resolution techniques that will provide sub-diffraction resolutions because it will provide better insight into the cellular structure, morphology and composition. Structured Illumination Microscopy(SIM) is one such established technique. Existing work in super resolution phase imaging using SIM is exclusively limited to holography and interferometry based techniques. However, such methods require two-beam interference, illumination sources with high coherence, high experimental stability and phase unwrapping in the postprocessing step to retrieve the true object phase. In this work, we demonstrate a single beam propagation based super resolution phase imaging technique by applying structured illumination to Transport of Intensity Equation. It is valid under partial coherence, and does not require interference, simplifying the experimental and computational requirement. We have designed an upright microscope to demonstrate high resolution phase imaging of human cheek cells.

abstract: The research of this dissertation has involved the nanoscale quantitative characterization of patterned magnetic nanostructures and devices using off-axis electron holography and Lorentz microscopy. The investigation focused on different materials of interest, including monolayer Co nanorings, multilayer Co/Cu/Py (Permalloy, Ni81Fe19) spin-valve nanorings, and notched Py nanowires, which were fabricated via a standard electron-beam lithography (EBL) and lift-off process. Magnetization configurations and reversal processes of Co nanorings, with and without slots, were observed. Vortex-controlled switching behavior with stepped hysteresis loops was identified, with clearly defined onion states, vortex states, flux-closure (FC) states, and Omega states. Two distinct switching mechanisms for the slotted nanorings, depending on applied field directions relative to the slot orientations, were attributed to the vortex chirality and shape anisotropy. Micromagnetic simulations were in good agreement with electron holography observations of the Co nanorings, also confirming the switching field of 700-800 Oe. Co/Cu/Py spin-valve slotted nanorings exhibited different remanent states and switching behavior as a function of the different directions of the applied field relative to the slots. At remanent state, the magnetizations of Co and Py layers were preferentially aligned in antiparallel coupled configuration, with predominant configurations in FC or onion states. Two-step and three-step hysteresis loops were quantitatively determined for nanorings with slots perpendicular, or parallel to the applied field direction, respectively, due to the intrinsic coercivity difference and interlayer magnetic coupling between Co and Py layers. The field to reverse both layers was on the order of ~800 Oe. Domain-wall (DW) motion within Py nanowires (NWs) driven by an in situ magnetic field was visualized and quantified. Different aspects of DW behavior, including nucleation, injection, pinning, depinning, relaxation, and annihilation, occurred depending on applied field strength. A unique asymmetrical DW pinning behavior was recognized, depending on DW chirality relative to the sense of rotation around the notch. The transverse DWs relaxed into vortex DWs, followed by annihilation in a reversed field, which was in agreement with micromagnetic simulations. Overall, the success of these studies demonstrated the capability of off-axis electron holography to provide valuable insights for understanding magnetic behavior on the nanoscale. / Dissertation/Thesis / Ph.D. Materials Science and Engineering 2010

No description available.

Corrosion-related degradation incurs a significant cost to infrastructure and society. In 2016, the direct corrosion cost was estimated at $276 billion, which is 3.1% of the U.S. gross domestic product. Despite the known consequences of corrosion damage, many unknowns still exist, such as the mechanisms and rates of chloride-induced corrosion initiation and propagation. There is also a lack of high-quality quantitative kinetic data and analysis that can obtain the fundamental micro- and nanostructural mechanisms and initiation of metal corrosion. The corrosion initiation in metals is considered to be governed by dynamic processes that take place at the nanoscale. Thus, the measurement of nanoscale surface structures correlated with electrochemical properties in metals is critical in the understanding of corrosion initiation, and microstructure-corrosion relationship, as well as efforts toward materials design for corrosion mitigation. As a fundamental approach to this study, a systematic review of different surface characterization techniques was initially discussed. This entailed their principles, applications, and perspectives for surface corrosion monitoring, enabling the development of next-generation inhibition technologies, and improving corrosion predictive models. Unprecedented, this research study presented a novel application of a quantitative phase microscopy technique, spectral modulation interferometry (SMI), for in situ nanoscale characterization of corrosion of different alloys in real-time. SMI offers high sensitivity, rapid image acquisition, and speckle-free images; thus, real-time quantification of surface topography evolution during corrosion can be obtained accurately to evaluate the temporally- and spatially-dependent corrosion rates. With an innovative additive-manufactured fluid cell, experiments were performed under flowing solution conditions. Electrochemical tests via stepwise polarization and solution chemistry through collected aliquots of outflow solution were also performed alongside the nanoscale SMI experiment to simultaneously provide corroborating corrosion rate measurements. This innovative approach to measuring dissolution rates of metal at three levels can provide highly quantitative kinetic data of reacting surfaces that are rarely explored in the literature. First, the in situ SMI combined with the stepwise potentiostatic tests and the solution chemistry analysis was used to investigate the nanoscale characterization of corrosion of an AA6111-T4 aluminum alloy in real-time. The corrosion experiment was conducted in a 0.5 wt.% NaCl flowing solution acidified to pH ⁓2.9 by acetic acid. Based on the quantitative 3D height profiles across the corroded surface, pit formation resulting from rapid local corrosion was predominant, which is heterogeneously distributed and was appearing at different times. The computed time-dependent dissolution rates of aluminum also varied as the experiment proceeded, with the combination of linear and nonlinear surface normal distributions. An initial mean linear dissolution rate of (0.40 ± 0.007) μmol m−2 s−1 transitioned to a more rapid mean rate of (1.95 ± 0.035) μmol m−2 s−1, driven by the anodic polarization. Dissolution rates from the three performed methods follow similar trends and there is the visibility of linking the nanoscale in situ SMI data to the electrochemical corrosion measurements and ex situ chemical solution analysis. At the end of the corrosion period, rates of 118, 71, and 2.45 μmol m−2 s−1 were obtained from electrochemical measurements, ex situ solution analyses, and in situ SMI corrosion measurements, respectively. In addition, SMI–electrochemical experiments were performed to evaluate the effect of thermal history on corrosion modes and rates of AA6111. Quantitative estimates of the corrosion initiation and propagation in the alloy were also assessed. A single coil of AA6111 alloy that was solution heat treated at a temperature above 500°C and quenched with 2 different water quench rates (i.e., slow-quenched at 131ºC/s and fast-quenched at 506ºC/s) with each in T4 and T82 temper condition was investigated in this study. Irrespective of the quenched and/or temper conditions, the electrochemical potential-current (E-i) results showed a similar pattern in the polarization curve and similar current response over the immersed time, and a small difference in their corrosion behavior will be difficult to detect due to the dissolution kinetics that takes place on the nanoscale. As revealed from the SMI topography map, the corrosion modes at the nanoscale were very distinct despite having similar electrochemical responses and chemical compositions. Primarily, heterogeneous dissolution of intergranular corrosion (IGC) and crystallographic pitting was observed in the tested alloy substrates, with the slow-quenched samples susceptible to IGC and the fast-quenched samples susceptible to crystallographic pitting. The nucleation of IGC sites is triggered by the increased coarsening and formation of precipitates in the grain boundary, while the pitting corrosion is attributed to the coarsening of the precipitates in the grain bodies. The quantitative analysis of topography evolution from the SMI data revealed a non-uniform (i.e., heterogenous) surface dissolution, as is typical for aluminum alloys. Notably, the fast-quenched material resisted corrosion initiation for a longer time and showed great resistance even at higher anodic polarization. However, an instant breakdown then occurred after 60mV of polarization and corrosion accelerated faster, relative to the slow-quenched material which initiated sooner (i.e. with less overpotential). In this setup, it is now possible to detect and evaluate these differences quantitatively through a quick corrosion test with the combined electrochemical-SMI technique. Therefore, this work showed that the corrosion susceptibility of AA6111 alloy is influenced by the thermal history, which can be controlled with a proper quench rate and further tempering. Additionally, this research also utilized the novel SMI techniques to investigate in situ chloride-induced corrosion of A615 low-carbon steel at the nanoscale. Along with surface topography monitoring, a potentiostat was connected to simultaneously monitor the bulk electrochemical activity of the carbon steel. Experiments were conducted in chloride-free and chloride-enriched solutions at pH 5 to investigate the role of chloride on topography evolution, dissolution mode, and corrosion kinetics. The 3D topography map acquired from the SMI showed an early formation of localized shallow pits on the surface subjected to the chloride free-solution. A more detrimental form of corrosion was obtained on the samples in chloride-enriched solution, which revealed early-age microcracks or intergranular defective sites associated with the heterogeneous roughening of the sample surface. The presence of chloride ions also influenced the initiation period of corrosion. Indeed, higher grain defects were obtained in samples immersed in 5.0 wt.% NaCl solution than the sample in 1.0 wt.% NaCl solution. The quantitative analysis of the height profile data (acquired from SMI) verified the heterogeneity of the corrosion process of both samples either susceptible to pitting corrosion and/or intergranular corrosion behavior. A faster dissolution rate was acquired on the sample immersed in 5.0 wt.% NaCl solution, with the rate of (3.53 ± 0.103) μmol m−2 s−1 and (5.64 ± 0.0225) μmol m−2 s−1 computed at the initiation and propagation stages, respectively. Likewise, the estimated volume loss followed a similar trend to the 3D surface topography data, but a distinct behavior in the volume loss was observed when compared to the void volume obtained from the electrochemical monitoring. This confirmed that the electrochemical measurement overestimates metal loss and does not present a good representation of material dissolution on the nanoscale. Finally, a different perspective of corrosion mitigation in the metallic alloy was presented. The extensive application of deicing salts has led to significant deterioration in many transportation infrastructures and automobiles due to corrosion. In this regard, the work investigated the corrosion inhibition performance of 2 corn-derived polyols, namely: sorbitol, and mannitol, on reinforced steel rebar. The results demonstrated that the incorporation of polyols in the deicing solution reduced the corrosion initiation while the inhibition rate increased as the polyol content increased from 0% to 5wt.%. The outcome of this study contributed to the search for mitigation strategies to minimize the impact of deicing chemicals on steel infrastructures. Overall, it is evident that corrosion is a huge durability problem and requires significant consideration when designing metals or alloys that are usually exposed to hostile environments. Understanding the nanostructural and kinetics of corrosion at both the initiation and propagation periods, as well as its thermodynamics, is important for designing a suitable protection strategy. This dissertation is expected to present the application of the surface technique to directly quantify the dynamic evolution of site-specific local corrosion of metals during early initiation stages at the nanoscale. / Doctor of Philosophy / Corrosion-related degradation incurs a significant cost to infrastructure and society. In 2016, the direct corrosion cost was estimated at $276 billion, which is 3.1% of the U.S. gross domestic product. Despite the known consequences of corrosion damage, many unknowns still exist, such as the mechanisms and rates of chloride-induced corrosion initiation and propagation. There is also a lack of high-quality quantitative kinetic data and analysis that can obtain the fundamental micro- and nanostructural mechanisms and initiation of metal corrosion. The corrosion initiation in metals is considered to be governed by dynamic processes that take place at the nanoscale. Thus, the measurement of nanoscale surface structures correlated with electrochemical properties in metals is critical in the understanding of corrosion initiation, and microstructure-corrosion relationship, as well as efforts toward materials design for corrosion mitigation. As a fundamental approach to this study, a systematic review of different surface characterization techniques was initially discussed. This entailed their principles, applications, and perspectives for surface corrosion monitoring, enabling the development of next-generation inhibition technologies, and improving corrosion predictive models. Unprecedented, this research study presented a novel application of a quantitative phase microscopy technique, spectral modulation interferometry (SMI), for in situ nanoscale characterization of corrosion of different alloys in real-time. SMI offers high sensitivity, rapid image acquisition, and speckle-free images; thus, real-time quantification of surface topography evolution during corrosion can be obtained accurately to evaluate the temporally- and spatially-dependent corrosion rates. With an innovative additive-manufactured fluid cell, experiments were performed under flowing solution conditions. Electrochemical tests via stepwise polarization and solution chemistry through collected aliquots of outflow solution were also performed simultaneously with the nanoscale SMI experiment to provide corroborating corrosion rate measurements. This innovative approach to measuring dissolution rates of metal at three levels simultaneously can now provide highly quantitative kinetic data of reacting surfaces that are not explored in the literature.

Spectral interferometry, also known as spectral-domain white light or low coherence interferometry, has seen numerous applications in sensing and metrology of physical parameters. It can provide phase or optical path information of interest in single shot measurements with exquisite sensitivity and large dynamic range. As fast spectrometer became more available in 21st century, spectral interferometric techniques start to dominate over time-domain interferometry, thanks to its speed and sensitivity advantage. In this work, a dual-modality phase/birefringence imaging system is proposed to offer a quantitative approach to characterize phase, polarization and spectroscopy properties on a variety of samples. An interferometric spectral multiplexing method is firstly introduced by generating polarization mixing with specially aligned polarizer and birefringence crystal. The retardation and orientation of sample birefringence can then be measured simultaneously from a single interference spectrum. Furthermore, with the addition of a Nomarski prism, the same setup can be used for quantitative differential interference contrast (DIC) imaging. The highly integrated system demonstrates its capability for noninvasive, label-free, highly sensitive birefringence, DIC and phase imaging on anisotropic materials and biological specimens, where multiple intrinsic contrasts are desired. Besides using different intrinsic contrast regime to quantitatively measure different biological samples, spectral multiplexing interferometry technique also finds an exquisite match in imaging single anisotropic nanoparticles, even its size is well below diffraction limit. Quantitative birefringence spectroscopy measurement over gold nanorod particles on glass substrate demonstrates that the proposed system can simultaneously determine the polarizability-induced birefringence orientation, as well as the scattering intensity and the phase differences between major/minor axes of single nanoparticles. With the anisotropic nanoparticles' spectroscopic polarizability defined prior to the measurement with calculation or simulation, the system can be further used to reveal size, aspect ratio and orientation information of the detected anisotropic nanoparticle. Alongside developing optical anisotropy imaging systems, the other part of this research describes our effort of investigating the sensitivity limit for general spectral interferometry based systems. A complete, realistic multi-parameter interference model is thus proposed, while corrupted by a combination of shot noise, dark noise and readout noise. With these multiple noise sources in the detected spectrum following different statistical behaviors, Cramer-Rao Bounds is derived for multiple unknown parameters, including optical pathlength, system-specific initial phase, spectrum intensity as well as fringe visibility. The significance of the work is to establish criteria to evaluate whether an interferometry-based optical measurement system has been optimized to its hardware best potential. An algorithm based on maximum likelihood estimation is also developed to achieve absolute optical pathlength demodulation with high sensitivity. In particular, it achieves Cramer-Rao bound and offers noise resistance that can potentially suppress the demodulation jump occurrence. By simulations and experimental validations, the proposed algorithm demonstrates its capability of achieving the Cramer-Rao bound over a large dynamic range of optical pathlengths, initial phases and signal-to-noise ratios. / PHD / Optical imaging is unique for its ability to use light to provide both structural and functional information from microscopic to macroscopic scales. As for microscopy, how to create contrast for better visualization of detected objects is one of the most important topic. In this work, we are aiming at developing a noninvasive, label-free and quantitative imaging technique based on multiple intrinsic contrast regimes, such as intensity, phase and birefringence. Spectral multiplexing interferometry method is firstly introduced by generating spectral interference with polarization mixing. Multiple parameters can thus be demodulated from single-shot interference spectrum. With Jones Matrix analysis, the retardation and orientation of sample birefringence can be measured simultaneously. A dual-modality phase/birefringence imaging system is proposed to offer a quantitative approach to characterize phase, polarization and spectroscopy properties on a variety of samples. The high integrated system can not only deliver label-free, highly sensitive birefringence, DIC and phase imaging of anisotropic materials and biological specimens, but also reveal size, aspect ratio and orientation information of anisotropic nanoparticles of which the size is well below diffraction limit. Alongside developing optical imaging systems based on spectral interferometry, the other part of this research describes our effort of investigating the sensitivity limit for general spectral interferometry based systems. The significance of the work is using Cramer-Rao Bounds to establish criteria to evaluate whether an optical measurement system has been optimized to its hardware best potential. An algorithm based on maximum likelihood estimation is also developed to achieve absolute optical pathlength demodulation with high sensitivity. In particular, it achieves Cramer-Rao bound and offers noise resistance that can potentially suppress the demodulation jump occurrence.

Polarization-dependence provides a unique handle for extending the dimensionality of optical microscopy, with particular benefits in nonlinear optical imaging. Polarization-dependent second order nonlinear optical processes such as second harmonic generation (SHG) provide rich qualitative and quantitative information on local molecular orientation distribution. By bridging Mueller and Jones tensor, a theoretical framework was introduced to experimentally extend the application of polarization-dependent SHG microscopy measurements toward in vivo imaging, in which partial polarization or depolarization of the beam can complicate polarization analysis. In addition, polarization wavefront shaping was demonstrated to enable a new quantitative phase contrast imaging strategy for thin transparent samples. The axially-offset differential interference contrast microscopy (ADIC) was achieved as a combination of classic Zernike phase contrast and Nomarski differential interference contrast (DIC) methods. The fundamentally unique manner of this strategy also inspired rapid volumetric analysis in time dimension that is accessible for most existing microscopy systems. Finally, the dimensionality of high speed twophoton fluorescence imaging was extended to the spectral domain by spatial/spectral multiplexing, enabling beam scanning two photon fluorescence microscopy with 17 frames per second rate and over 2000 effective spectral data points.<br>

Ces travaux de thèse, consacrés à l'étude et analyse quantitative d'images de phase obtenues par interférométrie à décalage quadri-latéral, ont pour but la caractérisation d'un point de vue métrologique d'un outil de mesure et de ses différentes applications. Cette technique d'interférométrie, développée initialement par la société Phasics pour les marchés de la métrologie optique et de la caractérisation de faisceaux laser essentiellement, peut aussi permettre d'obtenir la cartographie d'un champ électromagnétique complexe grâce à une mesure de front d'onde. En l'utilisant sur un microscope en condition d'imagerie, ont été obtenues des images de l'intensité et de la différence de chemin optique introduite par un échantillon semi-transparent, définissant ainsi une nouvelle technique de contraste de phase quantitatif. La première partie de cette thèse sera consacrée aux techniques en microscopie qui permettent une quantification. Nous verrons les enjeux de l'obtention de ce caractère quantitatif et ce qu'il signifie dans le cadre de différentes techniques utilisant la fluorescence. On étudiera la mesure dans le cadre d'une approximation dite "projective" réalisant certaines hypothèses. On verra quelles sont les grandeurs accessibles grâce à une mesure dans le cadre de cette approximation et quelles applications en biologie peuvent être développées concernant les éléments isotropes dans une première partie et les éléments anisotropes dans une seconde partie.Nous démontrerons la possible transposition de ces applications réalisées en deux dimensions en trois dimensions avec une résolution axiale suffisante permettant une reconstruction tomographique. / The aim of this thesis, dedicated to the study and quantitative analysis of phase images obtained thanks to quadri-wave lateral shearing interferometry, is to caracterize a metrological tool and its three proposed different applications.This work has been done in collaboration between Institut Fresnel (Marseille, France) and Phasics company (Palaiseau, France) and continues that of Pierre Bon who has been in charge the application this technique to microscopy. This interferometric technique, developped by Phasics, for optical metrology and lasers characterization, allows to record complex eletromagnetic field maps thanks to a wave front measurement. By using it in the microscope image plane, one can obtain inetnsity and optical path difference images of a semi-transparent biological sample. this technique is now considered as a new quantitative phase contrast technique.The first part of this manuscript will be a state of the art of quantitative microscopy techniques. The issues of quantification and its meanings in the framework of different fluorescent and phase based techniques will be discussed.A description of the technique that is used and its comparison with similar phase techniques will be done.The measurement, under the projective approximation, is studied leading to different variables. We show different applications concerning isotropic elements in a first part and anisotropic elements in the second one.We show how this measurement is trnasposed to the third dimensions allowing three dimensional imaging and complete reconstruction of refractive index maps of biological samples.

Práce se zabývá interpretací kvantitativního fázového zobrazení pomocí techniky koherencí řízené holografické mikroskopie. Vzhledem k tomu, že tato technika generuje velké množství kvantitativních fázových obrazů o nezanedbatelné velikosti, manuální analýza by byla časově náročná a neefektivní Za účelem urychlení analýzy obrazů získaných pomocí koherencí řízené holografické mikroskopie je v této práci navržena metodika automatizované interpretace kvantitativních fázových obrazů pomocí strojového učení s učitelem. Kvantitativní fázové obrazy umožňují extrakci parametrů charakterizujících distribuci suché hmoty v buňce a poskytují tak cennou informaci o buněčném chování. Cílem této práce je navrhnout metodologii pro automatizovanou klasifikaci buněk při využití této kvantitativní informace jak ze statických, tak z časosběrných kvantitativních fázových obrazů. Navržená metodika byla testována v experimentech s živými buňkami, jimiž byla vyhodnocena výkonnost klasifikace a významnost parametrů získaných z kvantitativních fázových obrazů.