The dissertation is concerned with the description and utilization of interference of two coherent optical rays. In addition, the conditions of coherence and its connections with the occurance of interference are discussed. Michelson's interferometer is used for the practical utilization of the interference effect. The possibility of measuring relatively small changes is demonstrated - deviation of piezocrystal, measurement of the coherent length of optical source and measurement of the index of refraction of tramsparent materials. The manner of optical coherent detention and its utilization in optical communication systems is indicated. After demonstration of the principle was carried out the measuring of detection of optical signal modified by the external modulator.

This diploma thesis deals with the algorithms for signal processing in a field of a low-coherence interferometry. The introductory part is devoted to the basic principle of the low-coherence interferometry and to presenting its field of applications. The second part contains a list of selected algorithms supplemented by a description of their functionality. The procedure of experimental measurement of known surface with Michelson interferometer is described in the third part and the results obtained for particular algorithms are presented. Finally, algorithms are compared on the basis of measurement results.

The aim of diploma thesis are modifications in mechanical design of the coherence controlled holographic microscope which will lead to reduction of some deficiencies. In this thesis there is a brief description of the history interference microscopy and differences between each types of interference microscopes. In this work there are stated some design deficiencies of actual condition of the microscope and also several solutions are suggested and shortly described. Then the best solution is chosen which is adjusted to a final form. It is described in detail and then realized. There is a summary included in the conclusion whether the new solution is suitable and if it fulfills the required condition.

L’imagerie échographique a connu un fort développement ces dernières années. Elle possède une cadence d’imagerie allant jusqu’à plusieurs milliers d’images par secondes notamment avec l’émergence des méthodes dites ultrarapides. Il s’agit donc de la modalité la plus adaptée pour des applications cardiaques permettant non seulement la reconstruction d’images mais également l’extraction de paramètres pour la caractérisation tissulaire, comme l’anisotropie locale présente dans le cœur. En effet, cet arrangement fibreux peut être modifié dans le cas de pathologies cardiaques. L’objectif de ce travail de doctorat est le développement d’une méthode d’extraction par imagerie ultrasonore 3D de l’orientation locale d’un milieu anisotrope. Cette approche doit permettre l’imagerie avec un large champ de vue pour être appliquée en imagerie cardiaque. Enfin, la validation de la chaîne de traitement est nécessaire. Pour répondre à ces problématiques, plusieurs solutions ont été proposées. Tout d’abord, l’orientation locale a été évaluée grâce à une méthode de cohérence spatiale permettant l’estimation de l’orientation dans un plan parallèle à la surface de la sonde. Une fois mise au point et validée, cette stratégie a été étendue afin d’extraire l’orientation locale en 3D et non uniquement l’angle dans un plan. Enfin, l’étude de différents types de transmissions a également été effectuée dans le but d’élargir le champ de vue imagé. Toutes ces méthodes originales ont été appliquées et validées sur des données acquises sur fantôme et in vivo. Ainsi, la détermination de l’orientation locale d’un milieu anisotrope a tout d’abord été réalisée sur un fantôme monodirectionnel puis sur le biceps d’un volontaire. Pour cela, un système expérimental constitué de quatre échographes de recherche a été élaboré grâce à la mise en commun d’équipements de CREATIS et du LabTAU, un autre laboratoire Lyonnais, afin d’acquérir des données en 3D. Ces travaux ont ainsi permis l’extension au cas d’une orientation non parallèle à la surface de la sonde d’un milieu anisotrope ainsi qu’une amélioration en termes de taille de champ de vue de la méthode existante. La validation de toute la chaîne de traitement a été réalisée. L’application au tissu cardiaque in vivo s’inscrit dans les directes perspectives des travaux / Ultrasound imaging has strongly developed in recent years. It reaches now a frame rates of several thousand images per second, thanks to the emergence of ultrafast imaging. It is therefore the most suitable modality for cardiac applications. Not only does it allow the reconstruction of images, it also enables the extraction of parameters for tissue characterization, such as local anisotropy inside the heart muscle. Indeed, this fibrous layout can be modified in the case of cardiac pathologies. The aim of this doctoral work is the development of a method to extract the local orientation of an anisotropic environment by 3D ultrasound imaging. This approach should allow imaging with a wide field a view to be applied in cardiac imaging. Finally, the validation of the processing chain is necessary. To address these issues, several solutions have been proposed. First, the local orientation was evaluated using a spatial coherence method. It allowed assessing the orientation of fibres in a plane parallel to the surface of the probe. Once developed and validated, this strategy was extended to extract the local orientation in 3D and not only the angle in a plane. Finally, the study of different types of transmissions was also carried out in order to widen the imaged field of view. All these original methods have been applied and validated on phantom and in vivo data: the determination of the local orientation of an anisotropic environment was first performed on a monodirectional phantom and then on the biceps of a volunteer. For this purpose, an experimental system consisting of four research ultrasound scanners was developed thanks to the sharing of equipment from CREATIS and LabTAU, another laboratory in Lyon, in order to acquire 3D data. This work has thus made it possible both to extend an anisotropic environment to the case of an orientation not parallel to the surface of the probe and to improve the size of the field of view of the existing method. The validation of the entire processing chain has been completed. Applying this method to in vivo cardiac tissue is directly part of future studies

Cette thèse s’inscrit dans le contexte des travaux visant à réduire la durée d’impulsion des lasers XUV générés dans des plasmas au domaine femtoseconde. La bande spectrale très étroite du milieu amplificateur limite la durée minimum accessible (limite de Fourier). Le milieu amplificateur des lasers XUV sont des plasmas denses et chauds qui peuvent être créés aussi bien par décharge électrique rapide que par différents types de lasers de puissance. Il existe ainsi 4 types de sources lasers XUV distinctes dont les paramètres du plasma (densité, température) dans la zone de gain diffèrent. Or, les propriétés spectrales et temporelles du rayonnement émis sont fortement liées à ces paramètres. L’ensemble des 4 types de lasers XUV opèrent en mode d'amplification de l'émission spontanée (ASE) et 2 d'entre eux peuvent opérer en mode « injecté ». Cette technique consiste à injecter une impulsion harmonique d'ordre élevé femtoseconde, résonante avec la transition laser, à l'une des extrémités du plasma amplificateur. L'important désaccord entre la largeur spectrale du plasma et celle de l'harmonique ne permet pas de conserver la durée fs de cette dernière au cours de l'amplification. Les simulations (code Bloch-Maxwell COLAX) montrent que l'amplification est fortement non-linéaire dans ces systèmes, avec notamment l'apparition d’oscillations de Rabi. La génération d'oscillations de Rabi dans des lasers XUV en mode injecté est actuellement considérée comme un moyen prometteur de produire des lasers XUV fs, mais la manifestation de ces dernières n’a toutefois encore jamais été mise en évidence expérimentalement. Ainsi, une méticuleuse caractérisation expérimentale des propriétés spectrales des 4 types de lasers XUV en relation avec les conditions du plasma, associée à une meilleure compréhension des mécanismes d’amplification sous différentes conditions plasma basée sur des études théoriques et des simulations, sont nécessaires pour atteindre notre objectif. Une large campagne expérimentale visant à caractériser spectralement l'ensemble des différents types de lasers XUV a été menée par notre groupe sur la dernière décennie. La résolution spectrale nécessaire n'étant pas accessible avec les spectromètres actuels, la méthode employée consiste à mesurer la cohérence temporelle du laser XUV par autocorrélation du champ électrique à l'aide d'un interféromètre à division de front d'onde, spécifiquement conçu pour ces mesures, à partir desquelles la largeur spectrale peut être déduite. Le dernier type de laser XUV (PALS, Prague) a été caractérisé dans le cadre de cette thèse. Le temps de cohérence mesuré est de 0,68 ps, significativement inférieur aux valeurs mesurées sur les autres types de lasers XUV. L'analyse de l'ensemble des mesures a fait apparaître un comportement différent suivant que la durée d’impulsion est longue devant le temps de cohérence ou proche de celui-ci. Dans le premier cas les largeurs spectrales déduites sont en bon accord avec les calculs, dans le second l’accord est moins bon et la forme des traces d'autocorrélation n'était pas comprise. Ces observations ont motivé une étude détaillée de l'influence des propriétés temporelles de l'émission ASE des lasers XUV sur la méthode interférométrique employée pour caractériser leur largeur spectrale. Cette étude, basée sur un modèle emprunté aux lasers à électrons libres, a révélé un effet de la cohérence temporelle partielle sur les mesures d'autocorrélation en champ de ces sources. Elle ouvre des perspectives sur l'utilisation de notre méthode pour une mesure simultanée de la largeur spectrale et de la durée d'impulsion de la source. Enfin, une étude basée sur un modèle Bloch-Maxwell a été réalisée pour tenter de mieux comprendre les conditions d'apparition des oscillations de Rabi au cours de l'amplification de l'harmonique dans le plasma de laser XUV. Deux régimes d'amplification, adiabatique et dynamique, autour d'un seuil d'inversion de population ont été mis en évidence. / The work of this thesis was made in the context of the efforts made to reduce the pulse duration of plasma-based XUV lasers down to the femtosecond domain. The very narrow spectral width of the amplifier medium (~ 1E10 - 1E11 Hz) limits the minimum achievable pulse duration (Fourier limit). The amplifier medium of XUV lasers pumped by collisional excitation are dense and hot plasmas that can be created both by rapid electrical discharge and by different types of power lasers. There are thus 4 distinct types of XUV laser sources with different plasma parameters (density, temperature) in the gain region. Yet, the spectral and temporal properties of the emitted radiation are strongly linked to these parameters. All 4types of XUV lasers operate in amplification of spontaneous emission (ASE) mode, and 2 of them, for a few years, can operate in "seeded" mode. This technique consists in injecting a femtosecond high order harmonic pulse (the seed), resonant with the lasing transition, at one extremity of the plasma amplifier. Because of the major mismatch between the spectral width of the plasma and that of the seed the femtosecond duration of the latter is not preserved during amplification. Simulations (COLAX Maxwell-Bloch code) show that the amplification is highly non-linear in such systems, including the appearance of Rabi oscillations. Generating Rabi oscillations in seeded XUV lasers is currently considered a promising way to produce femtosecond XUV lasers. However Rabi oscillations have yet never been experimentally demonstrated. Thus, a meticulous experimental characterization of the spectral properties of the 4 types of XUV lasers in connection with the plasma conditions, combined with a better understanding of amplification mechanisms under different theoretical plasma conditions based on studies and simulations are needed to reach our goal. A wide experimental campaign aiming to spectrally characterize all different types of XUV lasers was conducted by our group over the past decade. The required spectral resolution is not available with the best current spectrometers, so the method we used consists on the measurement of the temporal coherence of the XUV laser through an electric field autocorrelation, using a wave front-division interferometer that was specifically designed for these measures, from which the spectral width can be deduced. The latter type of the four XUV laser types (PALS, Prague) was characterized during this thesis, closing this experimental campaign. The measured coherence time was 0.68 ps, which is significantly lower than the coherence times measured on the other XUV laser types. Analysis of the overall results revealed two different behavior whether the XUV laser has a long pulse duration compared to its coherence time or if the two durations are close. In the first case the inferred spectral widths are in good agreement with theoretical predictions, while in the second case the agreement was not as good and the shape of the electric field autocorrelation traces was not understood. This observation has prompted a detailed study of the influence of temporal properties of ASE XUV lasers on the interferometric methodology used to determine the spectral width of XUV lasers. The study, based on a model developed for X-free electron lasers, revealed an effect of partial temporal coherence in electric field autocorrelation measures of these sources. This study offers perspectives on a simultaneous measure of the spectral width and the duration of theses sources with our method. Finally, a study based on Maxwell-Bloch equations was carried out in order to understand better the conditions of apparition of Rabi oscillations. This study highlighted two amplification regimes, adiabatic and dynamic, around a population inversion threshold.

The purpose of this study is to describe and explore the happiness, sense of coherence and resilience of rural teachers from a positive psychology framework where positive and healthy adaptation is emphasized. This study forms part of the dissemination phase of a longitudinal study known as STAR (Supportive Teachers Assets and Resilience). Completed questionnaires by twelve rural teachers in STAR schools (2 primary and 1 secondary) in rural Mpumalanga were purposively sampled as data sources for secondary analysis. The measures included the Oxford Happiness Questionnaire (OHQ), Resilience Scale (RS-14) and the Orientation to Life Questionnaire (SOC-13). Results are presented as descriptive and non-parametric statistics. Results indicated that teachers possess High Moderate to High levels of happiness, Moderate to High Moderate sense of coherence, and High Moderate to high levels of resilience. There was no significant relationship between happiness, sense of coherence and resilience. No significant differences were observed between levels of happiness, sense of coherence and resilience of teachers in (Pre- STAR intervention and post- STAR intervention); nor with regards to gender. Theorizing the findings of this study within the theoretical framework of positive psychology indicates that despite significant risk and adversity, teachers are able to demonstrate positive psychological constructs in the form of happiness (extraversion, kindness, humor, sense of purpose, aesthetic appreciation, locus of control, positive affect, self-efficacy, physical health and self-esteem ), sense of coherence (comprehensibility, manageability and meaning) and resilience (self-reliance, having a purposeful and meaningful life, equanimity, perseverance and existential aloneness). / Dissertation (MEd)--University of Pretoria, 2013. / gm2014 / Educational Psychology / unrestricted

In this thesis, an approach for developing single-photon sources at the 1550nm wavelength will be demonstrated, based on optical trapping of luminescent upconverting nanoparticles. A single-photon source is a source that emits a single photon at a time, and hence it is a source of quantum bits that constitutes the basic building units in quantum computers and quantum communications. The approach exploits the plasmonic properties of gold films and the waveguiding characteristics of single mode optical fibers (SMFs). We start by planar nanofabrication of subwavelength nanoapertures in a thin gold film based on finite difference time domain simulations for a peak transmission at the wavelength in question. Subsequently, using ultraviolet curable epoxy adhesion material, a nanoaperture patterned on a gold film can be transferred to an SMF tip forming a nanoantenna enhanced optical fiber tweezer (NAFT). As a final step in building the optical tweezer, a test of the capability of the integrated optical fiber tweezer to trap 20 nm, and 30nm polystyrene nanospheres, as well as luminescent upconverting nanoparticles (UCNPs), has been experimentally realized with encouraging results. In addition to the optical trapping of the luminescent nanoparticles, the nano aperture antenna can improve light coupling into the low loss optical fiber guiding channel. Also, it could have a positive influence on enhancing the photon emission rate through the Purcell effect. Furthermore, we have combined NAFT with a low insertion loss wave splitter, a wavelength-division multiplexer (WDM), to allow measuring the 1550nm photon-emission statistics on a cooled superconducting nanowire single-photon detector (SNSPD) at ~ 2.4o K. Eventually, nanoantenna enhanced optical fiber tweezers can play an essential role in optical trapping towards developing single-photon sources and the emerging technology of quantum information processing, computation, and cryptography. / Graduate

Bakgrund: Hjärtsvikt är en växande folksjukdom som drabbar allt fler individer i världen. Hjärtsvikt är ett tillstånd när hjärtat inte kan pumpa tillräckligt med blod för att tillgodose kroppens behov, vilket påverkar både hälsan och det vardagliga livet. För att sjuksköterskor ska kunna ge god vård till personer med hjärtsvikt krävs det kunskap och förståelse kring upplevelsen av att leva med hjärtsvikt. Syfte: Att beskriva personers upplevelse av att leva med hjärtsvikt.   Metod: En litteraturöversikt med utgång i forskning med kvalitativ design och induktiv ansats. Resultatartiklar insamlades från databaserna CINAHL, MedLine och PsycInfo som analyserades med hjälp av Fribergs femstegsanalys. Resultat: I resultatet uppkom tre teman och sex underteman. Dessa teman beskriver vilka förändringar hjärtsvikt förde med sig och hur det påverkade vardagen. Slutsatser: I litteraturöversikten framkom det olika aspekter av att leva med hjärtsvikt. Hjärtsvikt skapade begränsningar och emotionella förändringar i livet. Bristen på information från sjukvården försvårade hanteringen av hjärtsvikt. Nivå av KASAM kan påverka förutsättningar till att kunna hantera sjukdomen. För att underlätta omvårdnad och stöttning är det betydelsefullt att sjuksköterskor inneha kunskap och förståelse för upplevelsen av att leva med hjärtsvikt. / Background: Heart failure is a growing public health problem and is affecting many people around the world. Heart failure is a condition when the heart is unable to pump sufficiently to maintain blood flow to meet the body’s needs which affect the health and the daily life. For nurses to be able to provide good healthcare, it requires knowledge of experience of people living with heart failure. Aim: To describe people’s experience of living with heart failure. Method: A literature review based on qualitative design and inductive approach. Result articles were collected from the databases CINAHL, MedLine and PsycInfo and analyzed using Friberg’s five-step analysis. Result: The result revealed tree themes and six sub-themes. These themes describe how heart failure changed and affected everyday lives of people living with it. Conclusion: The literature study revealed various aspects of living with heart failure. Heart failure created limitations and emotional changes in life. The lack of knowledge from the healthcare made managing heart failure difficult. The level of SOC can affect the prerequisites of managing the disease. It is important that nurses have knowledge and understanding of the experience of living with heart failure, to facilitate nursing.

Beginning with the discovery of graphene, two-dimensional materials have amassed a strong interest. Like graphene, transition metal dichalcogenides (TMDs) can be coaxed into atomically thin sheets which have some impressive properties. Unlike graphene, TMDs also has a change in their electronic band structure causing an indirect band gap to a direct gap transition in its monolayer form. Additionally, these materials lose their inversion symmetry as a monolayer. These unique properties make TMDs a strong candidate for being used in optoelectronic and valleytronic devices. In order for these devices to be successful, the optical properties of TMDs must be thoroughly understood. Due to this class of material's strong Coulomb interaction, the optical properties are dominated by excitons, a quasiparticle made up of an electron-hole pair. Therefore, the success of these devices relies, in part, on understanding and manipulating excitons. One key parameter of excitons is their dephasing rate which characterizes the lifetime of the coherent superposition of two states (i.e. how the coherence decays which is caused by excitons interacting with their environment). In this work, two optical properties are investigated: (1) How the linear absorption of the TMDs A-exciton peak varies as the material increases in thickness. By looking at how the absorption varies by sample thickness, the interaction between emitters can be understood. Experimental results for the diamagnetic shift are presented which are used to determine the lateral excitonic size. Through theoretical calculations, based on the semiconductor Maxwell-Bloch equations, additional insight into the radiative coupling of the systems are obtained. (2) How the coherence prole of the exciton changes in the presence of an external magnetic eld and specic valley excitation. By varying the polarization scheme in the four wave mixing measurement, specic valley excitation can be selected, allowing for insight into the dephasing mechanisms. By applying an external magnetic eld, the energy levels of the electron and hole can be discretized and the corresponding eects on the system's coherence seen. In conjunction with time-dependent density function theory calculations and the experimental results, a deeper understanding of exciton dynamics and multi-exciton complexes was obtained. Finally, a new system is proposed in which complex spectroscopic techniques can be performed on micron sized samples as well as devices in the presence of an external magnetic eld at cryogen temperatures. This system will allow for the investigation of the optical properties of stacked monolayers (heterostructures) as well as devices.

Title of thesis: Clinical Effectiveness of the Schultz Autogenic Training on the Electrical Activity of the Brain Objectives: The thesis aims to analyze the impact of Schultz autogenic training on brain activity evaluated using EEG Course of action: To obtain the data, an experimental group containing 11 participants aged 20-30, disregarding gender, was created. Participants practiced Schultz autogenic training using the identical audio record once a day during the course of nine weeks. Upon completion of the training, all participants were subjected to one-off measurement by the Nicolet EEG instrument. Brain activity was measured before, during and after the training. Obtained EEG data were processed with NeuroGuide software using coherence analysis and fast Fourier transform. Coherence analysis provided charts mapping the electrical activity of Brodmann areas during the course of all three stages and fast Fourier transform yielded data of performance ratio between theta and alpha frequencies, so called T/A index. Performance ratio of the T/A index was subject to Student's paired t-test in order to draw final conclusion. T/A results show changes in the representation of alpha and theta waves during all measurements. Results: The results of the thesis were used to verify the veracity of stated...