Dissertations / Theses on the topic 'Multimode light'
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Wang, Qi. "Studies of multimode fibre linked white light interferometric sensor systems." Thesis, City University London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389649.
Full textZheng, Zhan. "Two-photon--two-atom excitation with quantum multimode light states." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066589/document.
Full textTwo-photonÐtwo-atom (2P2A) excitation turns out to be an important test bench of quantum optical properties. In 2004, Muthukrishnan et al. announced a great enhancement of the transition at 2P2A resonance, when an entangled two-photon state, coming from a three-level cascade, interacts with two non-interacting atoms. Their conclusion: in some situations, entanglement can replace a real interaction Hamiltonian, reveals an important property related to entanglement. In this thesis, We study in detail the efficiency of various multimode two-photon states of light to induce the simultaneous excitation of two atoms of different kinds under 2P2A resonance condition. We find that several separable, correlated states, produced either by an atomic cascade or parametric down-conversion, or even appropriate combinations of coherent states, have comparable efficiencies as the photon state produced by an atomic cascade. We conclude that the true physical origin of the enhancement is the frequency anti-correlations, neither the temporal correlations, time ordering, nor entanglement. To present, we are not sure whether or not the enhancement is a quantum effect. We also studied: 1. the optimized 2P2A transition probability for a given photon spectrum; 2. the influence coming from finite lifetimes of the excited detecting atoms; 3. the 2P2A transition probability in the presence of atomic interaction
Ning, Ya Nong. "A study of optical fibre interferometric systems using multimode laser diode light sources." Thesis, City University London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316037.
Full textWickenbrock, A. "Cold atoms in light fields : from free space optical lattices to multimode optical cavities." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1349525/.
Full textLeedumrongwatthanakun, Saroch. "Quantum information processing with a multimode fibre." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS526.
Full textTransport of information through a multimode optical fibre raises challenges when one wants to increase the data traffic using many spatial modes due to modal cross-talk and dispersion. Instead of considering those complex mixing of modes as a detrimental process, in this dissertation, we harness its mode mixing to process quantum optical information. We implement a reconfigurable linear optical network, a fundamental building block for scalable quantum technologies, based on an inverse photonic approach exploiting the technology of wavefront shaping. We experimentally demonstrate manipulation of two-photon quantum interference on various linear optical networks across both spatial and polarization degrees of freedom. In particular, we experimentally show the zero-transmission law in Fourier and Sylvester interferometers, which are used to certificate the degree of indistinguishability of an input state. Moreover, thanks to the ability to implement a non-unitary network, we observe the photon anti-coalescence effect in all output configurations, as well as the realization of a tunable coherent absorption experiment. Therefore, we demonstrate the reconfigurability, accuracy, scalability and robustness of the implemented linear optical networks for quantum information processing. Furthermore, we study the statistical properties of one-and two-photon speckles generated from various ground-truth states of light after propagating through a multimode fibre. These statistical properties of speckles can be used to extract information about the dimensionality, purity, and indistinguishability of an unknown input state of light, therefore allowing for state classification. Our results highlight the potential of complex media combined with wavefront shaping for quantum information processing
Heinrich, Georg [Verfasser], and Florian [Akademischer Betreuer] Marquardt. "Nanomechanics interacting with light: Dynamics of coupled multimode optomechanical systems / Georg Heinrich. Betreuer: Florian Marquardt." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2011. http://d-nb.info/101763923X/34.
Full textNeo, Poh Ling. "Increasing the transmission capacities of a multimode fibre transmission link using a spatial light modulator." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612421.
Full textChille, Vanessa. "Quantum optics with structured light." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066358/document.
Full textThis thesis aims at learning more about nonclassical structured light. Quantum optics and structured light are two topics that are subject to countless scientific examinations. However, they are very rarely combined and the quantum properties of structured light are not as thoroughly studied as they deserve. By structured light, we mean any light fields with complex transverse distributions of intensity, phase or polarization. We want to link the topics of quantum optics and structured light in this thesis. For this purpose, we experimentally generate particular nonclassical structured light fields. In particular, we construct an experimental setup that enables us, in principle, to produce arbitrary amplitude squeezed vector beams, i.e. light beams with a complex transverse structure of the state of polarization. Furthermore, we analyze spatial properties of light beams, and their quantum noise theoretically. We specifically perform theoretical examinations of the quantum noise in the width of a light beam. To show the feasibility of an experimental verification of our theoretical results, we conduct simulations for the measurement of spatial parameters of a beam's cross-section by a multipixel detector
Zhao, Xin. "Study of Multimode Extrinsic Fabry-Perot Interferometric Fiber Optic Sensor on Biosensing." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/34534.
Full text
In this thesis, a multimode fiber-optic sensor has been developed based on extrinsic Fabry-Perot interferometry (EFPI) for the measurement of optical thickness in self-assembled thin film layers as well as for the immunosensing test. The sensor was fabricated by connecting a multimode fiber (MMF) and a silica wafer. A Fabry-Perot cavity was formed by the reflections from the two interfaces of the wafer. The negatively charged silica wafer could be used as the substrate for the thin film immobilization scheme. The sensor is incorporated into the white-light interferometric system. By monitoring the optical cavity length increment, the self-assembled thin film thickness was measured; the immunoreaction between immunoglobulin G (IgG) and anti-IgG was investigated.
Master of Science
Czarske, Jürgen W., Daniel Haufe, Nektarios Koukourakis, and Lars Büttner. "Perspectives of multimode fibers and digital holography for optogenetics." SPIE, 2016. https://tud.qucosa.de/id/qucosa%3A34836.
Full textWang, K. "Design, measurement and analysis of multimode light guides and waveguides for display systems and optical backplane interconnections." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1435557/.
Full textTovar, Anthony Alan. "Off-axis multimode light beam propagation in tapered lenslike media including those with spatial gain or loss variation." PDXScholar, 1988. https://pdxscholar.library.pdx.edu/open_access_etds/3839.
Full textGouzien, Élie. "Optique quantique multimode pour le traitement de l'information quantique." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4110.
Full textThis thesis studies multimode quantum optics, from generation to detection of light. It focuses on three main parts. Multimode squeezed states generation within cavity is studied. More specifically, we take into account general quadratic Hamiltonian, which allows describing experiments involving arbitrary number of modes and pumps within a medium performing four-wave mixing. We describe a generic approach combining Green functions and symplectic matrix decomposition. This general theory is illustrated on specific cases. First, low-dimensional examples are given. Then, a synchronously pumped optical parametric oscillator (SPOPO) is described and studied; it shows a very distinct behavior from that of the SPOPO using second order non-linearity. This work opens way to the realization of quantum frequency combs with ring micro-resonators engraved on silicon. Single-photon detectors are described taking into account temporal degrees of freedom. We give positive-valued measurement operators describing such detectors including realistic imperfections such as timing-jitter, finite efficiency and dark counts. Use of those operators is illustrated on common quantum optics experiments. Finally, we show how time-resolved measurement allows improving the quality of state generated by single-photon heralded source. In the third part we propose a protocol for generating a hybrid state entangling continuous and discrete variables parts, for which the discrete part is time-bin encoded. This scheme is aanalysed in detail with respect to its resilience to experimental imperfections
Sperber, Tom. "Control of light in a disordered medium with gain : wavefront-shaping the pump in fiber amplifiers and fiber lasers." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS366.
Full textThe recent advent of wavefront-shaping techniques has demonstrated the ability to control the propagation of light through a broad range of complex media, amongst them multimode fibers. The case of a multimode fiber which is also a gain medium presents increased complexity, since the pump beam, in itself multimode, may act upon the signal light in speckle-like spatial profiles of amplification. The resulting heterogeneous gain may be viewed as analogous to a non-unitary scattering process. Interest in the study of such systems has recently risen in several domains, such as optical communications, high-power fiber lasers, and random lasers. In this work, we consider a multimode fiber doped by a rare-earth element, and pumped by a coherent pump beam that passes through a wave-front shaping scheme, rendering the modal composition of the excitation within the fiber configurable. We explore the possibility of harnessing the degrees of freedom thus offered in the pumping, for controlling the output signal of such a gain system. A theoretical model and its implementation as a numerical solver serve to quantify the degree of achievable control, as well as providing insights into the fundamental mechanisms limiting it. In an amplifier configuration, the experimental work successfully validated the model’s predictions by showing a significant effect of the wave-front shaping of the pump upon the speckle at the amplifier’s output. In the lasing cavity configuration, the experimental work demonstrated the ability of the pump modulation scheme to influence the lasing emission, in particular to favor or suppress chosen lasing modes
Al-Mamun, Mohammad Shah. "Development of a Miniature, Fiber-optic Temperature Compensated Pressure Sensor." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/71308.
Full textMaster of Science
Perret, Solveig. "Génération de lumière Supercontinuum dans le visible et l’ultraviolet dans des fibres optiques multimodes de silice dopée à saut d'indice." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD024.
Full textAlthough multimode non-linear propagation has been studied in multimode optical fibres since the 1970s, recent developments in materials and manufacturing techniques have greatly renewed interest in this area. In this thesis, we report the experimental study of nonlinear frequency conversion processes in multimode fibres to generate new spectral components in the near ultraviolet (UV-A) and visible spectral regions. Two particular studies have been carried out. In the first, a few-mode step-index fibre was studied with two pump laser sources at 532~nm and 1064~nm. Depending on the particular experimental conditions, the results with 532~nm pumping yielded either a broad multimode continuum spanning over 515--680~nm, or as series of discrete spectral components emitted in particular higher-order modes over the range 524--538~nm. And again depending on experimental conditions, when pumping at 1064~nm, experiments yielded either a broadband multimode continuum spanning over 560--2350~nm, or a series of discrete spectral peaks in higher-order modes observed simultaneously with continuous spectral broadening. In the second study, experiments studied nonlinear frequency conversion in a UV-grade silica glass photonic crystal fibre with pumping at 532~nm and 355~nm. Results for 355~nm pumping in particular yielded the generation of higher-order mode discrete spectral peaks over the range 350--379.7~nm. Additional experiments pumping the photonic crystal fibre microstructure cladding region yielded a Raman cascade continuum spanning 350--390~nm. The experimental work in this thesis was accompanied by theoretical calculations of intermodal phase matching, or simulations of pulses propagation in an optical fibre as required. This thesis contributes to the growing body of results showing the utility of nonlinear effects in multimode fibre to generate coherent radiation over broad spectral ranges
Verrier, Isabelle. "Influence de certains paramètres sur la propagation lumineuse dans les fibres optiques : fluctuations d'intensité en sortie de fibre multimodale." Saint-Etienne, 1988. http://www.theses.fr/1988STET4008.
Full textZanzi, Andrea. "Passive and active silicon photonics devices at TLC telecommunication wavelengths for on-chip optical interconnects." Doctoral thesis, Universitat Politècnica de València, 2020. http://hdl.handle.net/10251/149377.
Full text[ES] Las tecnologías ópticas son el eje vertebrador de los sistemas de comunicación mod- ernos que proporcionan acceso de alta velocidad a la Internet, interconexiones efi- cientes entre centros de datos y dentro de ellos. Además, se están expandiendo hacia campos de investigación crecientes y nuevos mercados como son las aplicaciones de comunicaciones por satélite, los LIDAR (Laser Imaging Detection and Ranging), la computación neuromórfica y los circuitos fotónicos programables, por nombrar algunos. La fotónica de silicio está considerada y aceptada ampliamente como una de las tecnologías clave para que dichas aplicaciones puedan desarrollarse. Como resultado, hay una fuerte necesidad de estructuras fotónicas básicas integradas que sean innovadoras, que soporten altas velocidades de transmisión y que sean más eficientes en términos de consumo de potencia, a fin de aumentar la capacidad de los circuitos integrados fotónicos de silicio. El trabajo desarrollado y presentado en esta tesis se centra en el diseño y la car- acterización de dispositivos avanzados pasivos y activos, para circuitos fotónicos integrados. La tesis consta de tres capítulos principales, así como de sendas sec- ciones de motivación y conclusiones que exponen los fundamentos y los logros de este trabajo. El capítulo uno describe el diseño y la caracterización de un modulador electro-óptico Mach-Zehnder incorporado en una unión pn vertical altamente eficien- ciente que explota el efecto de dispersión de plasma en banda O. El capítulo dos está dedicado al diseño y caracterización de una nueva geometría de dispositivo de interferencia multimodo asimétrico y su aplicación en un modulador Mach-Zehnder. El capítulo tres está dedicado al diseño y caracterización de innovadores cristales fotónicos unidimensionales para aplicaciones de modulación con luz lenta. Se pre- senta un amplio análisis de los principales retos derivados del uso de la misma.
[CA] Les tecnologies òptiques són l'eix vertebrador d'aquells sistemes de comunicació moderns que proporcionen accés d'alta velocitat a la Internet, així com intercon- nexions eficients inter i entre centres de dades. A més a més, s'estan expandint cap a camps d'investigació creixents i nous mercats com són les aplicacions de co- municacions per satèl·lit, els LIDAR (Laser Imaging Detection and Ranging), la computació neuromòrfica i els circuits fotònics programables, entre d'altres. La fotònica de silici és considerada i acceptada àmpliament com una de les tecnologies clau i necessàries perquè aquestes aplicacions puguen desenvolupar-se. Per aquest motiu, es fa necessària l'existència d'estructures fotòniques bàsiques integrades que siguen innovadores, que suporten altes velocitats de transmissió i que siguen més eficients en termes de consum de potència, a fi d'augmentar la capacitat dels cir- cuits integrats fotònics de silici. El treball desenvolupat i presentat en aquesta tesi se centra en el disseny i la caracterització de dispositius avançats passius i actius, per a circuits fotònics integrats. La tesi consta de tres capítols principals, així com d'una secció de motivació i una altra de conclusions que exposen els fonaments i els assoliments d'aquest treball. El capítol u descriu el disseny i la caracterització d'un modulador electro-òptic Mach-Zehnder incorporat en una unió pn vertical d'alta efi- ciència que explota l'efecte de dispersió de plasma en la banda O. El capítol dos està dedicat al disseny i caracterització d'una nova geometria de dispositiu d'interferència multimode asimètric així com a la seua aplicació en un modulador Mach-Zehnder. El capítol tres està dedicat al disseny i caracterització d'innovadors cristalls fotònics unidimensionals per a aplicacions de modulació amb llum lenta. S'inclou també una anàlisi detallada dels principals reptes derivats de l'ús d'aquest tipus de llum.
I want to thank you the Generelitat Valenciana and the European Project L3MATRIX for the funding, without them my doctorate would not taken place.
Zanzi, A. (2020). Passive and active silicon photonics devices at TLC telecommunication wavelengths for on-chip optical interconnects [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149377
TESIS
Štolzová, Hana. "Analýza limitů zobrazování multimodovými optickými vlákny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-392838.
Full textYusuf, Isse Jamila, and Ghouch Chaimae El. "Information Theoretic Similarity Measures for Robust Image Matching : Multimodal Imaging - Infrared and Visible light." Thesis, KTH, Teoretisk datalogi, TCS, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186450.
Full textDenna studie syftade till att undersöka tillämpligheten av tre olika informationsteoretiska likhetsmått vid matchning av bilder, mutual information (MI), cross cumulative residual entropy (CCRE) och sum of conditional variances (SCV). Ett experiment genomfördes för att bedöma hur de olika likhetsmåtten påverkades i kontexten av multimodalitet, i detta fall i samband med infrarött och synligt ljus. Detta uppnåddes genom att köra simuleringar av fyra olika scenarier med hjälp av bilder tagna i infrarött och synligt ljus, och dessutom med variationer i mängden detaljer för att skapa olika experimentella uppsättningar. Nämligen experimentuppsättning A: unimodala datamängder med mer / mindre detaljer och experimentuppsättning B: multimodala datamängder med mer / mindre detaljer. Resultatet visade att multimodalitet har en statistiskt signifikant påverkan på alla likhetsmått. Observationer gjordes att likhetsmåttens beteenden, när man försöker matcha bilder med olika mängd detaljer, skilde sig från varandra. Detta gav en grund för bedömning av vilken av dessa likhetsmått som då kunde användas för att ge de mest tydliga och stabila resultaten som möjligt beroende på variationen av mängden detaljer i datat. Med denna studie drogs slutsatsen att likhetsmåttet CCRE gav mest de tydliga och stabila resultaten i samband med multimodalitet gällande infrarött och synligt ljus för båda fallen av mer eller mindre detaljer. Även om de andra likhetsmåtten också gav goda resultat i vissa fall, skulle CCRE vara att rekommendera, som observerat i denna studie.
Toledo, Acosta Bertha Mayela. "Multimodal image registration in 2D and 3D correlative microscopy." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S054/document.
Full textThis thesis is concerned with the definition of an automated registration framework for 2D and 3D correlative microscopy images, in particular for correlative light and electron microscopy (CLEM) images. In recent years, CLEM has become an important and powerful tool in the bioimaging field. By using CLEM, complementary information can be collected from a biological sample. An overlay of the different microscopy images is commonly achieved using techniques involving manual assistance at several steps, which is demanding and time consuming for biologists. To facilitate and disseminate the CLEM process for biologists, the thesis work is focused on creating automatic registration methods that are reliable, easy to use and do not require parameter tuning or complex knowledge. CLEM registration has to deal with many issues due to the differences between electron microscopy and light microscopy images and their acquisition, both in terms of pixel resolution, image size, content, field of view and appearance. We have designed intensity-based methods to align CLEM images in 2D and 3D. They involved a common representation of the LM and EM images using the LoG transform, a pre-alignment step exploiting histogram-based similarities within an exhaustive search, and a fine mutual information-based registration. In addition, we have defined a robust motion model selection method, and a multiscale spot detection method which were exploited in the 2D CLEM registration. Our automated CLEM registration framework was successfully tested on several real 2D and 3D CLEM datasets and the results were validated by biologists, offering an excellent perspective in the usefulness of our methods
Kandoth, Noufal. "Design, Synthesis and Characterization of Photoactivable Cyclodextrin-Based Nanoparticles for Multimodal Anticancer Therapy." Doctoral thesis, Università di Catania, 2013. http://hdl.handle.net/10761/1280.
Full textOb'yedkova, Ekaterina. "Multimodal Environmental Interfaces : discrete and continuous changes of form, light, and color using natural modes of expression." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91410.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (page 75).
In this thesis, I defined and implemented a framework for design and evaluation of Multinodal Environmental Interfaces. Multimodal Environmental Interfaces allow users to control form, light, and color using natural modes of expression. The framework is defined by categorizing possible changes as discrete or continuous. Discrete and continuous properties of form, light, and color can be controlled by speech, gestures and facial expressions. In order to evaluate advantages and disadvantages of each of the modalities, I designed and conducted a series of experiments. I disproved my hypothesis that whereas discrete changes are easier to control with language, continuous changes are easier to control with gestures and facial expressions through a series of interactive prototypes. I proved my hypothesis that the perception of whether a gesture or a speech command feels intuitive is consistent among the majority of users.
by Ekaterina Ob'yedkova.
S.M.
Hott, Robert Shawn. "Re-tooling an American metropolis." [Tampa, Fla.] : University of South Florida, 2010. http://digital.lib.usf.edu/?e14.3368.
Full textTitle from PDF of title page. Document formatted into pages; contains 155 pages. The content of this file may cause problems when attempting to access it through some versions of the Internet Explorer or Firefox browser. Recommended browsers for accessing this file are Internet Explorer 8, Opera, Safari, or Chrome on Windows; Firefox, Opera, or Safari on Macs. Includes bibliographical references.
Hannachi, Ammar. "Imagerie multimodale et planification interactive pour la reconstruction 3D et la métrologie dimensionnelle." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD024/document.
Full textProducing industrially manufactured parts generates a very large number of data of various types defining the manufacturing geometries as well as the quality of production. This PhD work has been carried out within the framework of the realization of a cognitive vision system dedicated to the 3D evaluation of manufactured objects including possibly free form surfaces, taking into account the geometric tolerances and uncertainties. This system allows the comprehensive control of manufactured parts, and provides the means for their automated 3D dimensional inspection. The implementation of a multi-sensor (passive and active) measuring system enabled to improve significantly the assessment quality through an enriched three-dimensional reconstruction of the object to be evaluated. Specifically, we made use simultaneously of a stereoscopic vision system and of a structured light based system in order to reconstruct the edges and surfaces of various 3D objects
Alimi, Abib Olushola Yessou. "Imagerie tridimensionnelle en lumière polarisée : vers une analyse multi-échelle et multimodale avec l'imagerie par résonance magnétique pondérée en diffusion." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4025.
Full textDiffusion Magnetic Resonance Imaging (dMRI) is the only non-invasive and invivo imaging modality able to provide human brain structural connectivity information. This is done via an estimation of the fiber orientation distribution (FOD) of white matter and dMRI tractography. In this thesis, three-dimensional Polarized Light Imaging (3D-PLI) is investigated and, thanks to its high spatial resolution, is presented as a complementary and potential technique for validation and guidance of dMRI fiber orientation estimates and tracking. The main goal of this work is, thus, to propose a strategy to close the resolution gap between dMRI and 3D-PLI and to investigate metrics for their quantitative comparison and, henceforth, to pave the way for multiscale and multimodal image analysis.Contributions in this thesis are manifold. First, we study the 3D-PLI fiber orientation and propose a method to disentangle the sign ambiguity of its inclination angle for an accurate determination of the 3D orientation. Second, we introduce an analytical and fast technique to compute the FOD from microscopic 3D-PLI orientation estimates to the meso- or macroscopic dimensions of dMRI. Third, we perform tractography at multiple scales from 3D-PLI human brain data to demonstrate the preservation of the fiber tracts architecture regardless of the decrease in resolution. Finally, we investigate how these obtained tractograms can be inspected using homology theory for a quantitative evaluation between them. Overall, we develop original and efficient dMRI and 3D-PLI methods, validate on both synthetic and human data and lay the foundations for multiscale and multimodal studies between dMRI and 3D-PLI
Benmoussat, Mohammed Seghir. "Hyperspectral imagery algorithms for the processing of multimodal data : application for metal surface inspection in an industrial context by means of multispectral imagery, infrared thermography and stripe projection techniques." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4347/document.
Full textThe work presented in this thesis deals with the quality control and inspection of industrial metallic surfaces. The purpose is the generalization and application of hyperspectral imagery methods for multimodal data such as multi-channel optical images and multi-temporal thermographic images. In the first application, data cubes are built from multi-component images to detect surface defects within flat metallic parts. The best performances are obtained with multi-wavelength illuminations in the visible and near infrared ranges, and detection using spectral angle mapper with mean spectrum as a reference. The second application turns on the use of thermography imaging for the inspection of nuclear metal components to detect surface and subsurface defects. A 1D approach is proposed based on using the kurtosis to select 1 principal component (PC) from the first PCs obtained after reducing the original data cube with the principal component analysis (PCA) algorithm. The proposed PCA-1PC method gives good performances with non-noisy and homogeneous data, and SVD with anomaly detection algorithms gives the most consistent results and is quite robust to perturbations such as inhomogeneous background. Finally, an approach based on fringe analysis and structured light techniques in case of deflectometric recordings is presented for the inspection of free-form metal surfaces. After determining the parameters describing the sinusoidal stripe patterns, the proposed approach consists in projecting a list of phase-shifted patterns and calculating the corresponding phase-images. Defect location is based on detecting and analyzing the stripes within the phase-images
Mayer, Jürgen 1977. "Mesoscopic 3D Quantitative Imaging: Attenuation Correction with OPTiSPIM." Doctoral thesis, Universitat Pompeu Fabra, 2015. http://hdl.handle.net/10803/523519.
Full textAquesta tesi cobreix una sèrie de desenvolupaments tècnics, per a millorar l’adquisició i l’anàlisi d’imatges mesoscòpiques, centrant-se en l’obtenció quantitativa d’imatges. El tema principal és l’atenuació en microscòpia de làmina de llum fluorescent (LSFM). L’atenuació pot ser una causa important en el deteriorament de la senyal, tot i que cap de les millores tècniques existents en LSFM anaven adreçades a aquest problema directament. Hem abordat aquest problema mitjançant la fusió de la tomografia de projecció òptica (OPT) amb la microscòpia de pla d’il.luminació selectiva (SPIM) en un únic aparell híbrid (OPTiSPIM). A diferència de l’SPIM, que es basa en contrast de fluorescència, l’OPT permet recontruir dades del contrast d’absorbància. A part d’haver registrat dades multimodals mitjançant la fusió de dades de diferents mecanismes de contrast, el contrast d’absorció reconstruït obté un mapa d’atenuació en 3D de la mostra que permet la correcció del deteriorament de la senyal fluorescent obtinguda amb l’SPIM. Aquesta senyal corregida permet una mesura més acurada de la fluorescència de la mostra.
Schmittberger, Bonnie Lee. "Multimode Atomic Pattern Formation via Enhanced Light-atom Interactions." Diss., 2016. http://hdl.handle.net/10161/12108.
Full textThe nonlinear interaction between light and atoms is an extensive field of study with a broad range of applications in quantum information science and condensed matter physics. Nonlinear optical phenomena occurring in cold atoms are particularly interesting because such slowly moving atoms can spatially organize into density gratings, which allows for studies involving optical interactions with structured materials. In this thesis, I describe a novel nonlinear optical effect that arises when cold atoms spatially bunch in an optical lattice. I show that employing this spatial atomic bunching provides access to a unique physical regime with reduced thresholds for nonlinear optical processes and enhanced material properties. Using this method, I observe the nonlinear optical phenomenon of transverse optical pattern formation at record-low powers. These transverse optical patterns are generated by a wave- mixing process that is mediated by the cold atomic vapor. The optical patterns are highly multimode and induce rich non-equilibrium atomic dynamics. In particular, I find that there exists a synergistic interplay between the generated optical pat- terns and the atoms, wherein the scattered fields help the atoms to self-organize into new, multimode structures that are not externally imposed on the atomic sample. These self-organized structures in turn enhance the power in the optical patterns. I provide the first detailed investigation of the motional dynamics of atoms that have self-organized in a multimode geometry. I also show that the transverse optical patterns induce Sisyphus cooling in all three spatial dimensions, which is the first observation of spontaneous three-dimensional cooling. My experiment represents a unique means by which to study nonlinear optics and non-equilibrium dynamics at ultra-low required powers.
Dissertation
Liu, Hsin-You, and 劉信佑. "Multimode Emission of White Organic Light Emitting Diodes with Resonant Cavity structure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/32322633021884799506.
Full text國立成功大學
光電科學與工程研究所
96
In this study, we evaporate distributed bragg reflectors (DBR) using e-beam evaporator system, then we fabricate organic light emitting diodes (OLED) on DBR. Our resonant cavity OLED exhibit multimode emission, and spectral narrowing, enhancement of emitting intensity were observed due to the resonant effect. Finally, we measure the characteristic of the devices. In this study, we design suitable DBR reflector, and control the optical length of resonant cavity carefully. We add SiO2 filler layer to increase optical length, and make the resonant cavity device emit a white color consisting of multimode emission. The yield-current density(Y-J) characteristics of the four modes device showed the yield of 5.85cd/A at operation current density of 200A/m2 and its CIE also showed (x=0.33, y=0.32) at 8Volt with better performance in color-rendering index (CRI) of 82.17. The current efficiency was enhanced by 29% compared with conventional organic light emitting diodes(4.53cd/A) by the resonant effect. Our results clearly imply that by the reasonable design of the resonant cavity structure, it is possible to realize multimode emission of white organic light emitting diodes with even higher efficiency and better CRI.
Pinho, Cátia Manuela Rodrigues. "Optimized photonic integrated solutions for next generation optical systems." Doctoral thesis, 2019. http://hdl.handle.net/10773/29187.
Full textOs sistemas óticos de nova geração beneficiam com a otimização de fotónica integrada. Com os circuitos de fotónica integrada (PIC) avançados a surgir como uma tecnologia promissora, dentro da crescente procura por flexibilidade/ reconfigurabilidade dos sistemas óticos e redes de telecomunicações. Os sistemas óticos baseados em PIC oferecem soluções eficientes e rentáveis em resposta às necessidades crescentes de transmissão de dados. De modo a contribuir para o desenvolvimento tecnológico associado à fotónica integrada, são investigados no âmbito desta dissertação diferentes soluções otimizadas de PIC, abordando diferentes estágios do seu desenvolvimento, nomeadamente projeto/design, teste e encapsulamento. Técnicas de compressão de sinais óticos estão a progredir no sentido de apoiar a expansão de velocidade de processamento e quantidade de armazenamento com elevada largura de banda associada. São esperadas vantagens recorrendo a PIC para a implementação de transformadas óticas, e.g., transformada de Haar (HT). Esta necessidade motivou a investigação de soluções de PIC com design otimizado, desenvolvidas em plataforma integrada de nitreto de silício (Si3N4). O PIC desenhado é constituído por uma rede 2D a executar a HT para fins de compressão e uma rede de comutação para produzir todas as entradas lógicas esperadas para teste e caracterização. São propostos modelos de design otimizados para a estrutura elementar que compõe o PIC, i.e., componente de interferência multimodal. Adicionalmente, foi realizado o primeiro teste e caracterização experimental de um PIC implementando a HT para fins de compressão, numa plataforma integrada de fosfato de índio (InP) e num material orgânico-inorgânico híbrido. Tirando partido de um filtro sintonizável para compensação de dispersão, desenvolvido em plataforma integrada de Si3N4, foi demostrado um link de transmissão alargada (40 km) em modulação PAM-4, com possível aplicação em centros de processamento de dados de interconexão. A necessidade de medições precisas de desempenho para a caracterização efetiva de soluções integradas de ressoadores de elevado fator de qualidade, motivou a implementação de uma técnica de medição eficaz. Esta é baseada num interferómetro de Mach-Zehnder calibrado em rádio frequência e na realização de mediações de ganho de Brillouin por análise Lorentziana de ajuste de curva. Por fim, tendo em conta os rigorosos requisitos técnicos e funcionais associados ao teste/caracterização precisa de PIC e o facto de as atuais soluções serem dispendiosas e pouco flexíveis. Uma prova de conceito de uma nova plataforma flexível de encapsulamento por software é proposta com aplicação em processadores PIC e sistemas com multiplexagem por divisão espacial.
Programa Doutoral em Telecomunicações
Chistè, Elena. "Light emitting functionalized porous silicon microparticles as multimodal system in theranostics." Doctoral thesis, 2020. http://hdl.handle.net/11562/1012726.
Full textPlöchl, Michael. "Cognition in the Light of Perceptual and Behavioral Context." Doctoral thesis, 2015. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2015072313364.
Full textSchröder-Schetelig, Johannes. "Multimodal high-resolution mapping of contracting intact Langendorff-perfused hearts." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1551-8.
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