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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

Chats de Schrödinger d'un atome de Rydberg pour la métrologie quantique / Schrödinger cat states of a Rydberg atom for quantum metrology

Facon, Adrien 02 December 2015 (has links)
Il n'y a pas de limite fondamentale à une mesure classique : la position d'une aiguille sur un cadran peut être déterminée avec une incertitude arbitrairement faible. Au contraire, dans le monde quantique, la précision de toute mesure est limitée par le bruit quantique. Lorsque l'aiguille de mesure devient un système mésoscopique, tel un moment cinétique J qui évoluerait sur le cadran sphérique d'une sphère de Bloch, les fluctuations quantiques affectant les états cohérents conduisent alors à une incertitude de mesure en 1/√J appelée limite quantique standard. La métrologie quantique consiste à préparer l'aiguille dans un état quantique qui permet de dépasser cette limite et d'atteindre la précision ultime fondamentale, dite limite de Heisenberg, qui évolue en 1/J. Nous proposons et réalisons une approche innovante fondée sur la mesure de la phase relative d'une superposition d'états mésoscopiques du type Chat de Schrödinger. En utilisant un champ radiofréquence polarisé, nous avons en effet pu préparer un atome de Rydberg dans une superposition quantique du moment cinétique décrivant l'électron, dont la sensibilité au champ électrique approche la limite de Heisenberg. Cette méthode a permis la réalisation d'un électromètre à un seul atome mesurant de faibles champs de l'ordre du mV/cm en quelques dizaines de nanosecondes. La grande sensibilité de ces méthodes de mesure de champ résolue en temps et en espace ouvre la voie à de nombreuses applications. / There is no fundamental limit to the precision of a classical measurement. The position of a meter’s needle can be determined with an arbitrarily small uncertainty. In the quantum realm, fundamental fluctuations due to the Heisenberg principle limit the precision of any measurement. When the needle is replaced by a mesoscopic system, for instance a spin J evolving on a spherical dial, the Bloch sphere, the semi-classical spin coherent state quantum fluctuations lead to a measurement uncertainty scaling as 1/√J, the standard quantum limit (SQL). This is far from the ultimate Heisenberg limit (HL), which scales as 1/J. We present here an innovative approach, using interferometric measurements on mesoscopic Schrödinger-cat-like superpositions of Rydberg states to realize a single-atom electrometer measuring weak fields of the order of 1 mV/cm in a few tens of nanoseconds. The sensitivity of this method is beyond the SQL and we check that its uncertainty scales as the HL. The extreme sensitivity of this non-invasive space- and time-resolved field measurement could have many practical applications.
392

Métrologie et évaluation fonctionnelle motrice dans les maladies neuromusculaires de l’enfance : Illustrations à partir de la Mesure de Fonction Motrice (MFM) et d’une classification en grades de sévérité d’atteinte fonctionnelle motrice (NM-Score) / Metrology and motor function assessment in childhood neuromuscular diseases : Illustration with the Motor Function Measure (MFM) and a classification in levels of motor function decline severity (NM-Score)

Vuillerot, Carole 29 June 2012 (has links)
Les progrès de la recherche et de la prise en charge des maladies neuromusculaires de l’enfance ont prolongé la survie des patients. L’évaluation s’impose donc pour le suivi des patients et aussi en recherche clinique car les premiers essais cliniques tant attendus commencent à paraître. Une métrologie rigoureuse et adaptée est alors indispensable parce qu'il n'est possible ni de se contenter d’une quantification approximative ni d'utiliser des outils non adaptés à des pathologies évolutives. Nous résumons l’état des connaissances sur la métrologie appliquée à l’évaluation fonctionnelle motrice des patients atteints de maladies neuromusculaires et proposons une revue de la littérature sur les outils disponibles avec des analyses précises de leurs propriétés métrologiques. La Mesure de Fonction Motrice, développée à partir de 1998, présente des qualités intéressantes en termes de validité et de fiabilité. Nous avons analysé sa sensibilité au changement dans différentes populations de patients adultes et enfants. Nous proposons ensuite, une classification en grades de sévérité d’atteinte fonctionnelle motrice, le NM-score. Les études de validation ont confirmé son intérêt, sa facilité d'utilisation, sa validité et sareproductibilité. Le NM-Score permet de décrire précisément et de façon discriminante les patients en termes de fonction motrice pour la position debout et les transferts, la motricité axiale ou proximale et la motricité distale. S’intéresser à l’évaluation et à la mesure en médecine, c’est faire preuve d’une rigueur indispensable aux décisions de soins touchant des personnes vulnérables aux besoins spécifiques. / Advances in the research and treatment of childhood neuromuscular diseases have led to longer patient survivals. Evaluation is thus required not only in clinical practice for patient follow-up but also in medical research because the results of long-awaited clinical trials are beginning to emerge. A rigorous and appropriate metrology is then necessary because rough estimates or the use of improper assessment tools are no more satisfactory. We summarize here the current knowledge on the metrology applied to motor function assessment of patients with neuromuscular diseases. We propose a review of the literature on the tools available to monitor motor function with detailed analyses of their metrological properties. Developped since 1998, the Motor Function Measure presents interesting properties in terms of validity and reliability. We analyzed its sensitivity to change in different patient populations of adults and children. We then propose, the NM-Score, a classification in levels of severity of motor function decline.Validation studies have confirmed the interest of this score as well as its ease of use, validity,and reproducibility. The NM-Score is able to describe the patients precisely and discriminantly in terms of motor function for standing position and transfers, axial / proximal motor function and distal motor function. Being interested in evaluation and measurement in medicine is a sign of rigor necessary for decision-making regarding vulnerable persons with special need.
393

Probing chalcogenide films by advanced X-ray metrology for the semiconductor industry / Développement des protocoles de métrologie des nouveaux matériaux chalcogénures pour l'industrie des semi-conducteurs

Batista Pessoa, Walter 27 September 2018 (has links)
Les nouveaux matériaux de type chalcogénures (à base de S, Se, Te) font l’objet d’un intérêt croissant, non seulement pour les applications mémoires avancées, photonique et photovoltaïque, mais également autour des matériaux dichalcogénures innovants à base de métaux de transition (MoS₂, WS₂, ..). Les propriétés de ces matériaux, réalisés sous forme d’alliages binaires ou ternaires, avec ou sans dopage, dépendent fortement de leur composition, du profil de composition dans ces couches très fines, ainsi que des conditions de surface et d’interface (préparation, passivation). La maîtrise des propriétés de ces couches fines, déposées par voie chimique (CVD) ou par co-pulvérisation cathodique magnétron, doit s’appuyer sur des nouveaux protocoles de caractérisation aux incertitudes optimisées et compatibles avec un contrôle de fabrication en ligne. Dans cette thèse, nous présentons les performances de protocoles de métrologie spécifiquement développés pour l’analyse de couches minces de chalcogénures. Ces protocoles, qui s’appuient essentiellement sur les techniques non destructives de spectroscopie de photoélectrons (XPS) et de fluorescence X (XRF), ont été optimisés pour la caractérisation surfacique des couches ultrafines, l’analyse quantitative de la composition des matériaux complexes à base de tellure ou de soufre, et la mesure du profil de composition dans des couches et empilements < 50 nm. Dans un premier temps, nous présentons l’étude par XPS quasi in situ des propriétés de surface des matériaux Ge, Sb, Te ainsi que de leurs composés binaires et ternaires. Nous mettons en évidence l’évolution de la surface après remise à l’air puis vieillissement, et nous comparons l’efficacité de stratégies d’encapsulation in situ de couches minces à base de Te et Se. Nous démontrons ensuite les performances de protocoles d’analyses par XRF à dispersion de longueur d’onde (WDXRF) et XPS pour la quantification précise de la composition chimique de composés Ge-Sb-Te (de 1 à 200 nm) et de couches ultrafines de dichalcogénures à base de métaux de transition (MoS₂, WS₂). L’analyse combinée WDXRF/XPS permet de mesurer l’évolution avec la composition des facteurs de sensibilité relative des composantes Ge3d, Te4d et Sb4d, et par conséquent d’améliorer la précision de mesure par XPS de la composition des matériaux à changement de phase de type GexSbyTez. Nous soulignons également l’influence des effets de matrice sur la capacité de la WDXRF à l’analyse quantitative de l’azote dans des matériaux Ge-Sb-Te. Nous évaluons la possibilité d’un étalonnage de la WDXRF fondé sur des analyses par faisceaux d’ions spécifiques, ce qui permet in fine un suivi en ligne de couches GeSbTeN dans une fenêtre procédé donnée. Enfin, nous présentons deux stratégies de caractérisation non destructive du profil de composition dans des couches minces de chalcogénures. D’une part, nous démontrons que la combinaison des techniques de XRF en géométrie d'incidence rasante (GIXRF) et de réflectométrie X (XRR) permet une mise en évidence non ambiguë de faibles variations dans les procédés de dépôts, voire de phénomènes de diffusion dans des empilements de 10 nm d'épaisseur. L'utilisation de substrats multicouches en lieu et place du silicium permet d’optimiser la distribution en profondeur du champ d'ondes stationnaires, ce qui conduit à une amélioration nette de la sensibilité des stratégies XRR / GIXRF. D’autre part, nous montrons l’adéquation de protocoles fondés sur l’analyse XPS résolue en angle pour la caractérisation du profil de composition dans des couches nanométriques de GeTe et Ge₂Sb₂Te₅, ce qui permet une étude fine des premières étapes de dépôt de ces matériaux. / Chalcogenide materials are compounds based on S, Se, and Te elements from group VI of the periodic table. They are receiving an extensive interest not only for applications in resistive memories (PCRAM and CBRAM), photonics and photovoltaics but also in the development of new 2-D materials (e.g. spintronics applications). Chalcogenide materials are already present in the semiconductor roadmaps and it is already replacing flash memories (e.g. phase change material and ovonic threshold switch in new random access memory). For the next technology nodes, chalcogenide properties can be scaled by tuning the chemical composition or by reducing the film thickness. Nonetheless, it also means that their properties become more tightly influenced by the chemical composition, the surface/interface effects and the depth-profile composition. Hence, dedicated metrology protocols must be developed, first to assist the optimization of chalcogenide materials processes in cleanroom environment, then to allow non-destructive process monitoring with industry-driven uncertainties. In this PhD thesis, we developed metrology protocols based on X-ray techniques, dedicated to thin chalcogenides materials and fully compatible with inline monitoring. First, we used quasi in-situ X-ray Photoelectron Spectroscopy (XPS) to characterize the surface of Ge, Sb, Te thin materials and compounds, and to study the composition-dependent evolution of the surface after air break and ageing. The efficiency of in situ capping strategies to protect Te-based and Se-based thin layered materials from ageing was also investigated. Secondly, we demonstrated the ability of improved metrology strategies based on in-line Wavelength Dispersive X-ray Fluorescence (WDXRF) and XPS to accurately quantify the chemical composition of Ge-Sb-Te compounds (from 1 to 200 nm) and ultrathin 2D transition metal dichalcogenides (MoS₂, WS₂). Combined WDXRF/XPS analysis was used to determine refined values of composition-dependent relative sensitivity factors for Te4d, Sb4d and Ge3d that allow for XPS-based metrology of PCRAM materials with mastered accuracy. We pointed the need for in-depth study of the significant matrix effects that alter the ability of WDXRF to quantify Nitrogen in Ge-Sb-Te materials: ion beam analysis was carefully investigated as possible input for WDXRF calibration, and a WDXRF protocol was established for inline monitoring of N-doped Ge-Sb-Te films in a specific process window. Finally, we investigated two ways to non-destructively characterize the in-depth chemical distribution in thin chalcogenide films: we demonstrated that the combination of XRF in grazing incidence geometry (GIXRF) and X-ray reflectometry (XRR) was able to unambiguously reveal small process differences along with process-induced diffusion in 10 nm-thick stackings. We showed that the use of multilayered substrate instead of silicon allowed fine-tuning of the depth-dependent X-ray standing wave field, resulting in improved sensitivity of XRR/GIXRF strategies. We also developed an angle-resolved XPS protocol for the evaluation of the first deposition steps of GeTe and Ge₂Sb₂Te₅ films, revealing the process-dependent elemental distribution as a function of the film growth. Therefore, in this work we not only elaborated advanced metrology protocols for the development of new chalcogenide films but also metrological solutions for the next technology nodes (28 nm and below), since current in-line metrology tools reach their detection limits.
394

Algorithmes de références 'robustes' pour la métrologie dimensionnelle des surfaces asphériques et des surfaces complexes en optique / Robust Reference Algorithms for form metrology : Application to aspherical and freeform optics

Arezki, Yassir 05 December 2019 (has links)
Les formes asphériques et les surfaces complexes sont une classe très avancée d'éléments optiques. Leur application a considérablement augmenté au cours des dernières années dans les systèmes d'imagerie, l'astronomie, la lithographie, etc. La métrologie de ces pièces est très difficile, en raison de la grande gamme dynamique d'information acquise et la traçabilité à l'unité SI mètre. Elle devrait faire usage de la norme infinie; (Méthode de zone minimum ou la méthode Min-Max) pour calculer l'enveloppe entourant les points dans le jeu de données en réduisant au minimum la différence entre l'écart maximum et l'écart minimal entre la surface et l'ensemble de données. Cette méthode a une grande complexité en fonction du nombre de points, enplus, les algorithmes impliqués sont non-déterministes. Bien que cette méthode fonctionne pour des géométries simples (lignes, plans, cercles, cylindres, cônes et sphères), elle est encore un défi majeur lorsqu' utilisée pour des géométries complexes (asphérique et surfaces complexes). Par conséquent, l'objectif de la thèse est le développement des algorithmes d'ajustement Min-Max pour les deux surfaces asphériques et complexes, afin de fournir des algorithmes de référence robustes pour la grande communauté impliquée dans ce domaine. Les algorithmes de référence à développer devraient être évalués et validés sur plusieurs données de référence (Softgauges) qui seront générées par la suite. / Aspheres and freeform surfaces are a very challenging class of optical elements. Their application has grown considerably in the last few years in imaging systems, astronomy, lithography, etc. The metrology for aspheres is very challenging, because of the high dynamic range of the acquired information and the traceability to the SI unit meter. Metrology should make use of the infinite norm; (Minimum Zone Method or Min-Max method) to calculate the envelope enclosing the points in the dataset by minimizing the difference between the maximum deviation and the minimum deviation between the surface and the dataset. This method grows in complexity as the number of points in the dataset increases, and the involved algorithms are non-deterministic. Despite the fact that this method works for simple geometries (lines, planes, circles, cylinders, cones and spheres) it is still a major challenge when used on complex geometries (asphere and freeform surfaces). Therefore, the main objective is to address this key challenge about the development of Min-Max fitting algorithms for both aspherical and freeform surfaces as well as least squares fitting algorithms, in order to provide robust reference algorithms for the large community involved in this domain. The reference algorithms to be developed should be evaluated and validated on several reference data (softgauges) that will be generated using reference data generators.
395

Fundamental Studies of Copper Corrosion in Interconnect Fabrication Process and Spectroscopic Investigation of Low-k Structures

Goswami, Arindom 12 1900 (has links)
In the first part of this dissertation, copper bimetallic corrosion and its inhibition in cleaning processes involved in interconnect fabrication is explored. In microelectronics fabrication, post chemical mechanical polishing (CMP) cleaning is required to remove organic contaminants and particles left on copper interconnects after the CMP process. Use of cleaning solutions, however, causes serious reliability issues due to corrosion and recession of the interconnects. In this study, different azole compounds are explored and pyrazole is found out to be a potentially superior Cu corrosion inhibitor, compared to the most widely used benzotriazole (BTA), for tetramethyl ammonium hydroxide (TMAH)-based post CMP cleaning solutions at pH 14. Micropattern corrosion screening results and electrochemical impedance spectroscopy (EIS) revealed that 1 mM Pyrazole in 8 wt% TMAH solution inhibits Cu corrosion more effectively than 10 mM benzotriazole (BTA) under same conditions. Moreover, water contact angle measurement results also showed that Pyrazole-treated Cu surfaces are relatively hydrophilic compared to those treated with BTA/TMAH. X-ray photoelectron spectroscopy (XPS) analysis supports Cu-Pyrazole complex formation on the Cu surface. Overall Cu corrosion rate in TMAH-based highly alkaline post CMP cleaning solution is shown to be considerably reduced to less than 1Å/min by addition of 1 mM Pyrazole. In the second part, a novel technique built in-house called multiple internal Reflection Infrared Spectroscopy (MIR-IR) was explored as a characterization tool for characterization of different low-k structures.In leading edge integrated circuit manufacturing, reduction of RC time delay by incorporation of porous ultra low-k interlayer dielectrics into Cu interconnect nanostructure continues to pose major integration challenges. The main challenge is that porous structure renders interlayer dielectrics mechanically weak, chemically unstable and more susceptible to the RIE plasma etching damages. Besides the challenge of handling weak porous ultra low-k materials, a lack of sensitive metrology to guide systematic development of plasma etching, restoration and cleaning processes is the major stumbling block. We explored Multiple Internal Reflection Infrared Spectroscopy and associated IR techniques as a sensitive (sub-5 nm) characterization tool to investigate chemical bonding modification across fluorocarbon etch residues and low-k dielectric interface after plasma etching, ashing, UV curing and post-etch cleaning. The new insights on chemical bonding transformation mapping can effectively guide the development of clean-friendly plasma etch for creating ultra low-k dielectric nanostructures with minimal dielectric damages.
396

High Precision Comb-Assisted Molecular Spectroscopy in the Mid-Infrared

Alsaif, Bidoor 06 1900 (has links)
In several fields, such as biology, chemistry, combustion and environmental science, laser absorption spectroscopy represents an invaluable tool for the detection and identification of a variety of molecular species in the gas phase. For this detection to be quantitative, it is of paramount importance to rely on accurate spectroscopic parameters for the involved absorption lines in terms of line strength, line center frequency, pressure broadening, and pressure shift coefficients. The mid-infrared region offers the most favorable conditions for sensitive and chemically selective detection. The sensitivity derives from the presence of intense fundamental ro-vibrational transitions of molecules, whereas chemical selectivity relates to the unique absorption spectrum that molecules possess in the mid-IR region, thereby known as the fingerprint region. In this thesis, we combine the accelerating technology of optical frequency combs (OFC), which are powerful tools for accurate optical frequency measurements, with the wide tunability and single line emission in the mid-IR of extended cavity quantum cascade lasers (EC-QCL), to perform highly resolved, accurate and sensitive measurements in the fingerprint region, from 7.25 to 8 μm. Specifically, we have been able to lock for the first time the optical frequency of an EC-QCL to an OFC by utilizing nonlinear optics in the form of sum frequency generation (SFG) (Lamperti, AlSaif et al., 2018) and have exploited this comb-locked EC-QCL for an accurate survey of the entire ν1 ro-vibrational band of one of the most important greenhouse gases, nitrous oxide (N2O). The developed spectrometer is able to operate over a wide region of ~ 100 cm-1, in a fully automated fashion, while affording a 63 kHz uncertainty on the retrieved line center frequencies. The measurement allowed us to determine very accurately rotational constants of both ground and excited states of the ν1 band of N2O through the measurements of tens of lines of the P and R branches (AlSaif et al., JQSRT 2018). The spectrometer was then upgraded with a more recent and narrower linewidth EC-QCL to perform sub-Doppler saturated spectroscopy on the same N2O sample at a spectral resolution below 1 MHz, the sharpest ever observed with this type of laser. Finally, we worked at adding high sensitivity to the apparatus by introducing the gas in a high-finesse passive resonator and by developing a system to measure the intra-cavity absorption with cavity ring-down spectroscopy (CRDS) together with comb calibration.
397

Robotically Controlled Measurement System for Millimeter-Wave Antennas

Matos, Carmen January 2020 (has links)
No description available.
398

Pokročilé interferometrické metody pro souřadnicové odměřování / Advanced Interferometric Methods of Coordinates Measurement

Holá, Miroslava January 2018 (has links)
This thesis addresses particular topics in the field of the length metrology for nanometrology. Nanometrology deals with dimensional measurements of micro- and nanostructures with a high spatial resolution. It typically combines a microscope imaging with a precise coordinate measurement, usually capable of nanometre resolution using the state-of-art laser interferometry techniques. The development in this field is driven, among others, by emerging advanced nanotechnologies that demand to push further the capabilities and limits of the interferometric techniques to make the nanometre-level dimensional measurement of nanostructures possible. The principal limitations of current systems are the environmental conditions and especially the fluctuations in the refractive index of air. The theoretical part of this thesis aim at analysis of individual parts of laser interferometer. I oriented myself on the study of their advantages/disadvantages and further also the possibilities of their industrial applications. The second part of the thesis presents my work that focused on the influence of the refractive index of air (RIA) on the measurement uncertainty. I experimentally demonstrated an interferometric system with a self-cancellation RIA fluctuations: a transparent photodetector is used for the measurement of the standing wave along the axis of a passive resonator, where the resonator also serves as a reference for the laser wavelength stabilisation. Another optical arrangement, based on a setup of several Michelson interferometers, represents a combination of an interferometer and a refractometer into a single system. This setup was used to study the behaviour of the ambient airflow with respect to the optical path difference and physical separation of the interferometer’s and refractometer’s path. Based on the experimental results I proposed new arrangements for shape measuring interferometers, which combine length interferometry and a tracking refractometer for the direct compensation of RIA fluctuations with geometrically adjacent optical beams. The results indicate an improvement in RIA fluctuation induced uncertainty by a factor of 100. Third part describes the design and implementation of interferometric systems for specific applications. For the industrial environment I developed a compact interferometric displacement gauge which is designed to allow nanometre level measurement using a simplified interferometer construction. For coordinate measurement of the position of the sample up to six degrees of freedom, I realised a compact modular interferometric system, which represents a unique setup together with a stabilised laser source. To measure the position of the sample in an electron beam writer chamber, I designed and implemented a differential interferometer that works in the near infrared domain and uses a new detection method developed for this system. In the fourth part I describe the realisation of a high-speed interferometer with a differential arrangement, which allows evaluation of high-cycle fatigue in material engineering. This method of studying high-cycle fatigue should be beneficial for both the basic research and the engineering practice.
399

Génération et manipulation d'états photoniques intriqués pour la communication et la métrologie quantiques / Generation and manipulation of entangled photonic states for quantum communication and metrology

Mazeas, Florent 12 November 2018 (has links)
Après une première révolution quantique marquée par l'avènement de la physique quantique et de ses lois contre-intuitives, le monde du XXIe siècle est en proie à une seconde révolution articulée autour des technologies quantiques. Ces dernières promettent un bouleversement important dans les domaines de la communication, du calcul, de la simulation et de la métrologie. Dans cette thèse, nous abordons deux des quatre sous-domaines cités précédemment, à savoir ceux de la communication et de la métrologie quantique. Le mot d'ordre rassemblant ces travaux est l'intrication. En effet, nous montrons que, grâce à cette propriété fondamentale, les performances des systèmes de communication et de métrologie standards peuvent être surpassés. Ainsi, nous présentons comment générer ces états intriqués responsables de l'avantage quantique, et ce sur différentes plateformes technologiques. La première plateforme exploitée est le silicium. Récente pour la photonique, elle combine des avantages de maturité permettant l'intégration de nombreuses structures micrométriques sur une même puce, avec des propriétés non-linéaires, basés sur des processus d'ordre 3, efficaces. Le silicium se destine alors à de nombreuses applications comme nous le montrons en générant des paires de photons intriqués démultiplexés spectralement et directement compatibles avec les réseaux de télécommunications standards. La seconde plateforme que nous présentons est le niobate de lithium. Cette dernière, très exploitée dans bon nombres de travaux en photonique quantique, possède une efficacité de génération de paires de photons intriqués très importante, notamment grâce à l'exploitation de processus non-linéaires d'ordre 2. Nous détaillons une expérience de génération d'états hyper-intriqués, qui, à l'instar du silicium, est orientée vers le domaine de la communication quantique. Enfin, nous exploitons aussi ces paires de photons intriqués combinés à des méthodes d'interférométrie quantique afin de réaliser une expérience de métrologie quantique. Le but de cette dernière étant de mesurer avec une précision inédite la différence d'indices de réfraction de fibres bi-coeurs. / After a first quantum revolution marked by the advent of quantum physics and its counter-intuitive laws, the XXIst century is in the throes of a second quantum revolution based on quantum technologies. These promises a major upheaval in the areas of communication, calculation, simulation and metrology. In this thesis, we address two of the four subdomains mentioned above, namely those of communication and quantum metrology. The main word bringing together these works is entanglement. Indeed, we show that, thanks to this fundamental property, the performances of standard communication and metrology systems can be surpassed. Thus, we present how to generate these entangled states responsible for the quantum advantage, and this on two technological platforms. The first platform exploited is silicon. The latter, recent for photonics, combines the advantages of maturity allowing the integration of many micrometric structures on the same chip, with efficient non-linear properties, based on third order process. Silicon is then destined for many applications as we show by generating pairs of spectrally demultiplexed entangled photons directly compatible with standard telecommunication networks. The second platform we present is lithium niobate. The latter, widely used in many quantum photonics demonstrations, has a very important efficiency of entangled photon pairs generation, notably thanks to the exploitation of second order non-linear process. We detail an experiment of hyper-entangled states generation, which, like silicon, is oriented towards the domain of quantum communication. Finally, we also exploit these pairs of entangled photons combined with quantum interferometry methods to realize a quantum metrology experiment. The purpose is to measure with unprecedented precision the refractive indices difference of dual-core fibers.
400

THERMAL METROLOGY AND CHARACTERIZATION OF HIGH THERMAL CONDUCTIVITY POLYMER FIBERS AND FABRICS

Aaditya Candadai (10277555) 16 March 2021 (has links)
<p>Recent technological advances in the field of electronics and the accompanying trend of device miniaturization with enhanced functionality has led to growing interest in new methods of electronic device integration. As a result, flexible, wearable, and portable electronic devices have emerged as a way of providing a multifunctional infrastructure to facilitate various consumer needs, creating new challenges for materials development. Polymers possess a unique combination of desirable properties such as mechanical compliance, durability, low density and chemical stability which makes them ideally suitable as substrate materials to cater to such diverse applications. However, the low thermal conductivity of polymers hinders their heat spreading capability in thermal management applications for flexible and wearable devices. In recent years, there has been a growing interest in ultra-high molecular weight polyethylene (UHMW-PE) materials with aligned polymer chains due to their remarkably high thermal conductivity that is similar to some metals. These are commercially manufactured in large volumes as fibers using gel-spinning and ultra-drawing processes that impart a high degree of crystallinity and orientation to the polymer chains. As a result, these materials develop exceptionally high mechanical strength, elastic modulus, and thermal conductivity compared to conventional polymers. Therefore, UHMW-PE materials have found applications in commercial products like motorcycle gear and ballistic vests, but have not been commercially deployed for heat spreading and thermal management applications. While there has been much fundamental work on the development of high thermal conductivity fibers, effective translation of the high conductivity from individual fibers to macroscale (wearable) flexible fabrics has not been previously explored. The objective of this thesis is to obtain a fundamental understanding of the thermal transport properties of fabric materials constructed from the high conductivity polymer fibers, and assess their applicability for potential heat spreading applications. </p> <p>In the present work, commercially available high thermal conductivity fibers made of UHMW-PE are utilized to fabricate plain-weave fabrics prototypes, and the thermal properties of individual fibers, yarns, and woven fabrics are measured using a novel in-plane thermal measurement method. The characterization technique leverages infrared (IR) microscopy for a non-contact temperature sensing and is generally scalable for thermal characterization of the in-plane thermal-conductivity of materials across different length scales. Effective thermal conductivities on the order of ~10 Wm<sup>-1</sup>K<sup>-1</sup> are achieved along the in-plane dominant heat transport direction of the woven fabric, which is exceptionally high (~2-3 orders of magnitude) compared to conventional clothing and textile-based materials. The thermal conductivity and mechanical flexibility of the UHMW-PE fabrics are benchmarked with respect to conventional materials and the effect of bend-stressing and thermal annealing of the fabrics is characterization using the developed metrology. </p> <p>Additionally, a laser-based IR thermal metrology technique leveraging both non-contact heating and temperature sensing is conceptualized and validated using a numerical thermal modeling approach. The proposed technique provides an approach to estimate the in-plane heat spreading properties of anisotropic materials with direction-depended thermal properties based on quantifying the surface temperature map of a sample subjected to periodic heating. Numerical simulations are leveraged to demonstrate the applicability of this method to enable measurement of a wide range of thermal properties indicating great potential to develop this further as a standardized robust method for in-plane anisotropic thermal characterization of materials such as fabrics and films.</p> <p>This work sheds light on the high thermal conductivity of UHMW-PE materials that can be achieved using a scalable manufacturing process and describes the thermal metrology approaches to enable their characterization, thereby providing a foundation for the conceptualization and design of flexible substrate based thermal solutions in future wearable/flexible electronic devices.</p> <p> </p>

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