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Jiang, Shihong. "Non-scanning fluorescence confocal microscopy using laser speckle illumination." Thesis, University of Nottingham, 2005. http://eprints.nottingham.ac.uk/10139/.
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Confocal scanning microscopy (CSM) is a much used and advantageous form of microscopy. Although CSM is superior to conventional microscopy in many respects, a major disadvantage is the complexity of the scanning process and the sometimes long time to perform the scan. In this thesis a novel non-scanning fluorescence confocal microscopy is investigated. The method uses a random time-varying speckle pattern to illuminate the specimen, recording a large number of independent full-field frames without the need for a scanning system. The recorded frames are then processed in a suitable way to give a confocal image. The goal of this research project is to confirm the effectiveness and practicality of speckle-illumination microscopy and to develop this proposal into a functioning microscope system. The issues to be addressed include modelling of the system performance, setting up experiments, computer control and image processing. This work makes the following contributions to knowledge: * The development of criteria for system performance evaluation * The development of methods for speckle processing, whereby the number of frames required for an image of acceptable quality can be reduced * The implementation of non-scanning fluorescence confocal microscopy based upon separate recording of the speckle patterns and the fluorescence frames, demonstrating the practicality and effectiveness of this method * The realisation of real-time image processing by optically addressed spatial light modulator, showing how this new form of optical arrangement may be used in practice The thesis is organised into three main segments. Chapters 1-2 review related work and introduce the concepts of fluorescence confocal microscopy. Chapters 3-5 discuss system modelling and present results of performance evaluation. Chapters 6-8 present experimental results based upon the separate recording scheme and the spatial light modulation scheme, draw conclusions and offer some speculative suggestions for future research.
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Liu, Xiao-Long, Weibo Cheng, Massimo Petrarca, and Pavel Polynkin. "Universal threshold for femtosecond laser ablation with oblique illumination." AMER INST PHYSICS, 2016. http://hdl.handle.net/10150/622151.
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We quantify the dependence of the single-shot ablation threshold on the angle of incidence and polarization of a femtosecond laser beam, for three dissimilar solid-state materials: a metal, a dielectric, and a semiconductor. Using the constant, linear value of the index of refraction, we calculate the laser fluence transmitted through the air-material interface at the point of ablation threshold. We show that, in spite of the highly nonlinear ionization dynamics involved in the ablation process, the so defined transmitted threshold fluence is universally independent of the angle of incidence and polarization of the laser beam for all three material types. We suggest that angular dependence of ablation threshold can be utilized for profiling fluence distributions in ultra-intense femtosecond laser beams. Published by AIP Publishing.
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Hardy, Nicholas D. (Nicholas David). "Optimal standoff imaging using structured laser illumination and graphical models." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92965.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 241-246).<br>Structured illumination can be used to form images without using a lens or a detector array. A series of spatially-structured laser pulses is cast on the scene of interest, and a single-detector power measurement is made on the light each pulse returns from the scene. There has been significant interest in the "ghost imaging" configuration, in which the spatial patterns are randomly generated-e.g., by driving the pixels of a spatial light modulator with independent, identically-distributed pseudorandom inputs-and the sequence of measurements is correlated with reference versions of those patterns to image the scene. This naive reconstruction, however, is far from optimal for standoff imaging, for which rough-surfaced objects create laser speckle in the measurements. We develop a graphical model that encompasses the probabilistic relationships in structured-illumination standoff imaging along with an approximate message-passing algorithm for belief propagation to perform optimal scene reconstruction. This approach lets us accurately model the statistics of speckled images, photon detection, and atmospheric turbulence, as well as incorporate intelligent priors for the scene that capture the inherent structure of real-world objects. The result is state-of-the-art scene reconstructions.<br>by Nicholas David Hardy.<br>Ph. D.
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DILLEMANN, BENOIT. "Comportement dynamique du dioxyde de vanadium sous illumination laser impulsionnelle." Paris 7, 1995. http://www.theses.fr/1995PA077271.
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Transparent a temperature ambiante dans une large bande infra-rouge, le dioxyde de vanadium subit a 60c une transition de phase solide-solide le rendant totalement opaque a toute emission lumineuse. Le travail de recherche mene ici s'articule autour de trois axes complementaires de developpement, caracterisation et modelisation de ce compose. Afin d'obtenir des couches optiquement performantes, une partie du travail de these consiste a participer a l'elaboration de films de dioxyde de vanadium suivant deux procedes de fabrication originaux : une technique de pulverisation cathodique assistee sous bombardement ionique et une methode de synthese inorganique sous gaz reducteur inerte, les sol-gels. L'objet du volet experimental de cette etude est de caracteriser optiquement le materiau a l'etat passant et a l'etat bloque a l'aide de mesures quasistatiques visibles et infra-rouges puis de mettre en evidence la reponse dynamique de ces films a l'aide de sources laser impulsionnelles. Le modele rendant compte de la coupure d'une emission laser dans le dioxyde de vanadium requiert d'une part une connaissance approfondie de la physique des milieux stratifies sous illumination coherente puisqu'il a necessite un developpement supplementaire permettant d'effectuer un bilan d'energie detaille dans chaque couche de l'empilement. Il a necessite d'autre part une ecriture discrete par les differences finies du modele d'evolution thermique d'un milieu cylindrique prenant en compte la contribution instationnaire de la transition de phase solide-solide. Le caractere monotone de la transmittance optique en fonction de l'indice d'extinction d'une monocouche attenuante nous a conduit a determiner l'indice complexe du materiau.
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Kramer, Richard Dillon. "Annealing of radiation damaged gallium arsenide solar cells by laser illumination." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA289683.
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Nellas, Ioannis. "Terahertz imaging via a microbolometer camera under illumination of a quantum cascade laser." Thesis, Monterey, California. Naval Postgraduate School, 2010. http://hdl.handle.net/10945/5094.
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Approved for public release; distribution is unlimited<br>The terahertz (THz) region of the electromagnetic spectrum has not been fully utilized due to the lack of compact and efficient sources as well as detectors. This thesis aimed on characterizing a quantum cascade laser (QCL) beam and achieving high quality real-time THz imaging using a 160x120 pixel FLIR A20M microbolometer camera designed to operate in long wave infrared range. The FTIR spectroscopy of the QCL beam revealed that lasing could be achieved at 2.85 and 2.91 THz frequencies depending on the bias current. This behavior was analyzed using the longitudinal modes of the laser and found to correspond well with the experimental observations. Real-time imaging of concealed objects in transmission mode was accomplished using the silicon nitride-based microbolometer camera under illumination via the QCL with average power less than 1 mW. The larger extent of the object required the expansion of the narrow laser beam using a parabolic reflector and refocus on the camera using a second parabolic reflector. The standard Ge lens of the camera was replaced by a Tsurupica lens since the earlier lens was opaque to THz radiation. The real-time imaging can be extended to reflection mode as well as longer standoff distances using higher power THz lasers.
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Radenbach, Hannes N. "Radiative Behaviour of Gd2O3:Er/Yb nanoparticles under near infrared illumination." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16116.
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Mestrado em Ciência e Engenharia de Materiais<br>Upconverting nanoparticles have attracted much attention in science recently, specifically in view of medical and biological applications such as live imaging of cell temperatures or cancer treatment. The previously studied system of gadolinium oxide nanorods co-doped with erbium and ytterbium and decorated with different number densities of gold nanoparticles has been studied. So far, these particles have been proven as efficient nanothermometers in a temperature range from 300 up to 2000 K. In this work, a more detailed study on the morphological and radiative behaviour of these particles has been conducted. It was found that the laser power threshold for the onset of the black body radiation decreases strongly with the increase in the gold concentration. The temperature of the onset itself seems to remain approximately constant. The heating efficiency was determined to increase significantly with the gold concentration. The morphological study revealed that the temperature at the black body radiation threshold was not enough to induce any significant transformation in neither the nanorods nor the gold nanoparticles, as was expected from comparison with literature. However, significant changes in radiative properties and the morphology were detected for powders that underwent strong laser heating until the emission of brightly visible black body radiation.<br>Nanopartículas mostrando conversão ascendente de energia têm atraído recentemente muita atenção, sobretudo tendo em vista aplicações médicas e biológicas, tais como o mapeamento in vivo da temperatura intercelular ou o desenvolvimento de técnicas de diagnóstico de doenças cancerosas. O sistema estudado anteriormente de nanobastões de óxido de gadolínio co-dopados com érbio e itérbio e decorados com nanopartículas de ouro mostrou potencialidades como nanotermómetro eficaz numa gama de temperatura desde os 300 até aos 2000 K. Neste trabalho, um estudo mais detalhado do comportamento morfológico e radiativo destas partículas foi realizado. Verificou-se que o limiar de potência de laser para o início da radiação de corpo negro diminui fortemente com o aumento da concentração de ouro. A temperatura correspondente ao limiar do processo de emissão de corpo negro parece manter-se aproximadamente constante, independentemente da concentração de ouro à superfície dos nanobastões. A eficiência de aquecimento foi determinada, tendo-se mostrado que ela aumenta significativamente com a concentração de ouro. A análise morfológica aos nanobast˜oes revelou que a temperatura no limiar da radiação do corpo negro não é suficiente para induzir transformação significativas nem os nanobastões nem nas nanopartículas de ouro, como era de esperar partir da comparação com a literatura. No entanto, foram detetadas alterações significativas nas propriedades radiativas e na morfologia dos nanobastões decorados com a s nanopartículas de ouro que foram submetidos a forte aquecimento induzido pela excitação laser.
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Magalhães, Ana Carolina de. "Investigation of the influence of red and infrared illumination on mechanical properties of cells: Photobiomodulation." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-05012017-145626/.
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The photobiomodulation therapy (PBMT) has many demonstrated applications in the health area including anti-inflammatory and wound healing effects. The main objective of this work is to verify if the PBMT causes measurable changes in the mechanical properties of cells, specifically in red blood cells, epithelial cells and fibroblasts. In addition, to contribute to the knowledge of the action mechanisms of the PBMT, this study intends to support applications of the PBMT during invasive procedures, such as the direct photo-treatment of the blood in surgical procedures with cardiopulmonary bypass, regarding security of the cellular integrity. For this analysis, three experimental techniques were used: optical magnetic twisting cytometry (OMTC), defocusing microscopy and confocal laser-scanning microscopy. Human bronchial epithelial cells were evaluated with OMTC. The epithelial cell culture was either photo-treated or not, with red laser (lambda=660 nm), and fixed power and time (power density of 153 mW/cm2, time 300 s). It was not possible to observe significant differences between photo-treated and control epithelial cells, for the hysteresivity (ratio between the cell loss and elastic shear moduli). The defocusing microscopy, similar to a phase contrast microscopy, was used to study human red blood cells from fresh blood. The red blood cells were either photo-treated or not, with red laser (lambda=660 nm), and different powers and times (power densities from 0 to 510 mW/cm2, times from 0 to 180 s). Some morphological and mechanical characteristics of individual red blood cells were evaluated, such as volume, radial profile of cell thickness, lateral and vertical membrane fluctuations, for the photo-treated and control red blood cells. It was not possible to detect differences between the two groups, for any of the parameters analyzed. For both techniques, the absence of detectable differences might be due to several factors, such as the non-action of the PBMT, with the parameters used, in the epithelial cells and red blood cells or to the small sensitivity of each technique. Confocal laser-scanning microscopy was used to evaluate the actin filaments of mouse fibroblasts. The fibroblast cell culture was either photo-treated or not, with red (lambda=625 nm) or infrared (lambda=808 nm) light and fixed power and time (power density from 113 to 158 mW/cm2, time 300 s). The nucleus and cell areas increased slightly when comparing photo-treated and control cells. On the other hand, the total actin, total actin density and the number of filaments decreased. These changes were detected for a short time after treatment, however, after 24 h they are not anymore detectable. The total branch length does not seem to suffer any modifications. In summary, with the data acquired with the three techniques, it was found that the PBMT, in the red range, with the parameters used, could not cause noticeable changes in red blood cells and epithelial cells, in vitro. On the other hand, the PBMT in the red and near-infrared range, with the power and times used, cause changes in actin filaments of fibroblasts, in vitro, in particular the decrease of the total actin density.<br>A terapia por fotobiomodulação tem muitas aplicações na área de Saúde devido a sua ação anti-inflamatória e de reparação tecidual. O objetivo geral desse trabalho é verificar se a terapia por fotobiomodulação provoca mudanças nas propriedades mecânicas de células, em particular em hemácias, células epiteliais e fibroblastos. Além de contribuir com o conhecimento dos mecanismos de ação da terapia por fotobiomodulação, este estudo pretende subsidiar aplicações da terapia por fotobiomodulação durante procedimentos mais invasivos, como a iluminação direta do sangue em procedimentos cirúrgicos com circulação extracorpórea, sob o ponto de vista da segurança quanto à integridade celular. Para essa análise foram utilizadas três técnicas experimentais: citometria óptica magnética de oscilação (OMTC), microscopia de desfocalização e microscopia confocal. Com a técnica de OMTC foram avaliadas células epiteliais brônquicas humanas em cultura, foto-tratadas com laser vermelho (lambda=660 nm), com potência e tempo fixos (densidade de potência de 153 mW/cm2, tempo 300 s). Não foi possível constatar diferenças significativas entre as células epiteliais foto-tratadas e as células controle, para a histerisividade (razão entre os módulos viscoso e elástico das células). Com a técnica de microscopia de desfocalização, semelhante a uma microscopia de contraste de fase, foram estudadas hemácias humanas de sangue recém coletado. As hemácias foram tratadas com laser vermelho (lambda=660 nm), com potências e tempos variados (densidade de potência de 0 a 510 mW/cm2, tempo de 0 a 180 s). Foram avaliadas algumas características morfológicas e mecânicas das hemácias individualmente, como o volume, perfil radial de espessura, flutuações lateral e vertical da membrana, tanto para hemácias foto-tratadas quanto para hemácias controle. Não foi possível detectar diferenças entre as hemácias foto-tratadas e controle para nenhum dos parâmetros avaliados. Para ambas as técnicas, a falta de mudanças observáveis poderia ser devida a diversos fatores, como a não ação da terapia por fotobiomodulação nas células epiteliais e nas hemácias, com os parâmetros aqui empregados, ou à falta de sensibilidade de cada uma das técnicas usadas. A microscopia confocal foi utilizada para avaliar os filamentos de actina de fibroblastos de camundongo em cultura, os quais foram foto-tratados com luz vermelha (lambda=625 nm) ou infravermelha (lambda=808 nm) e potência e tempo fixos (densidade de potência de 113 a 158 mW/cm2, tempo 300 s). Foi possível constatar ligeiro aumento nas áreas nuclear e celular das células foto-tratadas em relação aos fibroblastos controle. Também foi possível verificar a diminuição da quantidade total de actina, densidade de actina e do número de filamentos de actina nos fibroblastos foto-tratados. Essas mudanças são detectadas para tempos curtos após o tratamento, sendo que depois de 24 h elas desaparecem. O tamanho total dos filamentos parece não sofrer alterações. A partir dos dados coletados com as três técnicas, foi possível constatar que a terapia por fotobiomodulação, com os parâmetros utilizados, não consegue provocar mudanças perceptíveis em hemácias e em células epiteliais, in vitro. Porém, causa mudanças nos filamentos de actina de fibroblastos, in vitro, em particular a diminuição da densidade de actina total.
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Chase, Charles T. "Annealing of defect sites in radiation damaged indium phosphide solar cells through laser illumination." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA306566.
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Graf, Alexander [Verfasser]. "Simultaneous Bulk Degradation and Regeneration of BO-LID and LeTID via Laser Illumination / Alexander Graf." Konstanz : KOPS Universität Konstanz, 2021. http://d-nb.info/1228271879/34.
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Luo, Ming. "Optical Analysis and Opto-Mechanical Design for Miniaturized Laser Illumination Module in 3D Areal Mapper." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/33169.
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A miniaturized spatial light modulator (SLM)-based structured-light illumination module with optical fiber input is designed to generate a coded 256 x 256 spots pattern for 3-D areal mapping applications. The projector uses the light from a He-Ne laser coupled to a polarization-maintaining (PM) fiber to illuminate a specially made hologram so that four virtual point sources are regenerated. The interference pattern of the four sources are filtered and modulated by an SLM. The output intensity can thus be encoded to form any arbitrary pattern through the electronic input applied to the SLM with a high speed. In this thesis, a complete optical diffraction analysis of the system is presented to provide guidelines for the optimal design of the system parameters. Through the theoretical analysis for square beam array generation, the important parameters for fabricating a hologram are given. The final system optical design and arrangement based on optical analysis are described. The detailed opto-mechanical construction of the LIM and the associated alignment, the computer simulation and the preliminary test results of the developed LIM are also provided.<br>Master of Science
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Revi, Frank. "Measurement of two-dimensional concentration fields of a glycol-based tracer aerosol using laser light sheet illumination and microcomputer video image acquisition and processing." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/69291.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1992.<br>Includes bibliographical references (leaves 48-49).<br>The use of a tracer aerosol with a bulk density close to that of air is a convenient way to study the dispersal of pollutants in ambient room air flow. Conventional point measurement techniques do not permit the rapid and accurate determination of the concentration fields produced by the injection of such a tracer into a volume of air. An instantaneous two dimensional distribution would aid in the characterization of flow and diffusion processes in the volume studied, and permit verification of theoretical models. A method is developed to measure such two dimensional concentration fields using a laser light sheet to illuminate the plane of interest, which is captured and processed using current microcomputer-based video image acquisition and analysis technology. Point concentrations, determined optically using extinction of monochromatic illumination projected through the aerosol onto a photo detector, are used to calibrate the captured video linages to detennine actual concentration values. Accuracy, reproducibility, and maximum rate of data acquisition are evaluated by means of theoretical models of ambient air flow in a sealed box with pointinjection of the tracer, and in a duct of circular cross section with constant air velocity under both constant and pulsed injection scenarios.<br>by Frank Revi.<br>M.S.
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Gläser, Philipp [Verfasser], Jürgen [Akademischer Betreuer] Oberst, Gregory [Akademischer Betreuer] Neumann, and Harald [Akademischer Betreuer] Hiesinger. "Evaluation of topography, slopes, illumination and surface roughness of landing sites near the lunar south pole using laser altimetry from the lunar reconnaissance orbiter / Philipp Gläser. Gutachter: Jürgen Oberst ; Gregory Neumann ; Harald Hiesinger. Betreuer: Jürgen Oberst." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1067388044/34.
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Gläser, Philipp Andreas [Verfasser], Jürgen [Akademischer Betreuer] Oberst, Gregory [Akademischer Betreuer] Neumann, and Harald [Akademischer Betreuer] Hiesinger. "Evaluation of topography, slopes, illumination and surface roughness of landing sites near the lunar south pole using laser altimetry from the lunar reconnaissance orbiter / Philipp Gläser. Gutachter: Jürgen Oberst ; Gregory Neumann ; Harald Hiesinger. Betreuer: Jürgen Oberst." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1067388044/34.
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Jobe, Oli. "Hyperbolic-umbilic diffraction catastrophe from oblate water drops with tilted illumination." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Summer2008/O_JOBE_073008.pdf.
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Rowan, Sheila. "Aspects of lasers for the illumination of interferometric gravitational wave detectors." Thesis, University of Glasgow, 1995. http://theses.gla.ac.uk/3422/.
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Chapter 1 of this thesis contains an introduction to the nature, sources and methods proposed for the detection of gravitational waves. Emphasis is placed on the techniques and noise sources associated with laser interferometric gravitational wave detectors and the resulting implications for the choice of a laser source for this type of detector. This information is mainly derived from the literature. Chapter 2 contains details of experiments to construct an electronic feedback system to stabilise the intensity at both low and high frequencies of a miniature diode-pumped monolithic Nd:YAG ring laser. This work was performed in collaboration with Dr Anne Campbell and Prof. Jim Hough, with advice on directly driving the diode laser from Charles Harb, (Australian National University, Canberra). Also described are investigations into the factors limiting the performance of the stabilisation systems. This was carried out with the added help of Ken Skeldon. Chapter 3 describes experiments to measure the frequency noise of a Nd:YAG ring laser at relaxation oscillation frequencies. Also described are investigations into the noise of a commercial Nd:YAG ring laser. These experiments were carried out in collaboration with Dr. Anne Campbell and Prof. Jim Hough. Chapter 4 describes experiments on the intracavity frequency doubling of a high power flashlamp-pumped Nd:YAG rod laser using different cavity designs. These experiments were carried out mainly by the author with some advice from Prof. Jim Hugh, Dr. Anne Campbell, Dr. Gavin Newton and Dr. Malcolm Gray (Australian National University, Canberra) and with some invaluable experimental help from Dr. J. Hong (formerly of the University of St. Andrews).
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Shangguan, Hanqun. "Novel Cylindrical Illuminator Tip for Ultraviolet Light Delivery." PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4647.
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The design, processing, and sequential testing of a novel cylindrical diffusing optical fiber tip for ultraviolet light delivery is described. This device has been shown to uniformly(+/- 15%) illuminate angioplasty balloons, 20 mm in length, that are used in an experimental photochemotherapeutic treatment of swine intimal hyperplasia. Our experiments show that uniform diffusing tips of < 400 micron diameter can be reliably constructed for this and other interstitial applications. Modeling results indicate that this design is scalable to smaller diameters. The diffusing tips are made by stripping the protective buffer and etching away the cladding over a length of 20 mm from the fiber tip and replacing it with a thin layer of optical epoxy mixed with A/203 powder. To improve the uniformity and ease of fabrication, we have evaluated a new device configuration where the tip is etched into a modified conical shape, and the distal end face is polished and then coated with an optically opaque epoxy. This is shown to uniformly scatter - 70% of the light launched into the fiber without forward transmission. To our knowledge, we are the first to use this device configuration, and we have achieved a uniform cylindrical pattern of laser energy with uniformity < ± 15% of the average value. A simple computational model suitable for the interpretation of laser energy irradiance along the bare core surface of multimode optical fiber tips is proposed and experimentally verified. The model used is based on geometrical optics and Gaussian approximation. Good agreement is obtained between the calculation and experiment. We have measured the optical properties of the tips through all the sequences of the fabrication. The performances of the diffusing tips for illuminating angioplasty balloons are then evaluated by Ultraviolet Light at 365 nm. A Ti:Sapphire Ring Laser System with a doubling crystal pumped by an argon ion laser is used to generate the wavelength in this study.
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Ait, Fqir Ali Fatima Zahra. "Développement et caractérisation de nouveaux procédés de passivation pour les capteurs d'images CMOS." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10186.
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La conception des futures générations de capteurs d'images CMOS, nécessite l'intégration de structures 3D telles que les tranchées profondes d'isolation, ou encore l'adoption de nouvelles architectures telles que les capteurs d'images à illumination face arrière. Cependant, l'intégration de telles architectures engendre l'apparition de nouvelles interfaces Si/SiO2, pouvant être la source d'un fort courant d'obscurité Idark, dégradant considérablement les performances électro-optiques du capteur. Ainsi, dans le but d'éliminer le Idark et d'augmenter l'efficacité de collecte et de confinement des photoporteurs au sein de la photodiode, la passivation de ces interfaces par l'introduction d'une jonction fortement dopée a été étudiée. D'une part, la passivation de la face arrière a été réalisée par implantation ionique activée par recuit laser pulsé. Grâce à un traitement très court et localisé, le recuit laser a démontré sa capacité à réaliser des jonctions minces et très abruptes. Une très bonne qualité cristalline ainsi que des taux d'activation avoisinant les 100% ont pu être atteint dans le mode fusion. Le mode sous-fusion quant à lui permet d'obtenir des résultats prometteurs en multipliant le nombre de tir laser. Les résultats électriques ont permis de distinguer les conditions optimales d'implantation et de recuit pour l'achèvement d'un faible niveau de Idark comparable à la référence en vigueur ainsi qu'une bonne sensibilité. Le deuxième axe d'étude s'est intéressé à la passivation des flancs des DTI par épitaxie sélective dopée in-situ. Des dépôts très uniformes de la cavité accompagnés d'une très bonne conformité de dopage le long des tranchées ont pu être réalisés. Les résultats sur lot électrique ont montré un très faible niveau de Idark supplantant la référence en vigueur<br>In order to maintain or enhance the electro-optical performances while decreasing the pixel size, advanced CMOS Image Sensors (CIS) requires the implementation of new architectures. For this purpose, deep trenches for pixel isolation (DTI) and backside illumination (BSI) have been introduced as ones of the most promising candidates. The major challenge of these architectures is the high dark current level (Idark) due to the generation/recombination centers present at both, DTI sidewalls and backside surfaces. Therefore, the creation of very shallow doped junctions at these surfaces reducing Idark and further crosstalk by drifting the photo-generated carriers to the photodiode region appears as key process step for introducing these architectures. For the backside surface passivation, a very shallow doped layer can be achieved by low-energy implantation followed by very short and localized heating provided by pulsed laser annealing (PLA). In the melt regime, box-shaped profiles with activation rates close to 100% and excellent crystalline quality have been achieved. The non-melt regime shows some potential, especially for multiple pulse conditions. In the optimal process conditions, very low level of Idark comparable to the standard reference has been achieved. In the other side, the passivation of DTI sidewalls has been performed by in-situ doped Epitaxy. Deposited layers with good uniformity and doping conformity all along the DTI cavity have been achieved. The electrical results show Idark values lower than the standard reference
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Frugier, Pierre Antoine. "Quantification 3D d’une surface dynamique par lumière structurée en impulsion nanoseconde. Application à la physique des chocs, du millimètre au décimètre." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112129.
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La technique de reconstruction de forme par lumière structurée (ou projection de motifs) permet d’acquérir la topographie d’une surface objet avec une précision et un échantillonnage de points dense, de manière strictement non invasive. Pour ces raisons, elle fait depuis plusieurs années l’objet d’un fort intérêt. Les travaux présentés ici ont pour objectif d’adapter cette technique aux conditions sévères des expériences de physique des chocs : aspect monocoup, grande brièveté des phénomènes, diversité des échelles d’observation (de quelques millimètres au décimètre). Pour répondre à ces exigences, nous proposons de réaliser un dispositif autour d’un système d’imagerie rapide par éclairage laser nanoseconde, présentant des performances éprouvées et bien adaptées. La première partie des travaux s’intéresse à analyser les phénomènes prépondérants pour la qualité des images. Nous montrons quels sont les contributeurs principaux à la dégradation des signaux, et une technique efficace de lissage du speckle par fibrage est présentée. La deuxième partie donne une formulation projective de la reconstruction de forme ; celle-ci est rigoureuse, ne nécessitant pas de travailler dans l’approximation de faible perspective, ou de contraindre la géométrie de l’instrument. Un protocole d’étalonnage étendant la technique DLT (Direct Linear Transformation) aux systèmes à lumière structurée est proposé. Le modèle permet aussi, pour une expérience donnée, de prédire les performances de l’instrument par l’évaluation a priori des incertitudes de reconstruction. Nous montrons comment elles dépendent des paramètres du positionnement des sous-ensembles et de la forme-même de l’objet. Une démarche d’optimisation de la configuration de l’instrument pour une reconstruction donnée est introduite. La profondeur de champ limitant le champ objet minimal observable, la troisième partie propose de l’étendre par codage pupillaire : une démarche de conception originale est exposée. L’optimisation des composants est réalisée par algorithme génétique, sur la base de critères et de métriques définis dans l’espace de Fourier. Afin d’illustrer les performances de cette approche, un masque binaire annulaire a été conçu, réalisé et testé expérimentalement. Il corrige des défauts de mise au point très significatifs (Ψ≥±40 radians) sans impératif de filtrage de l’image. Nous montrons aussi que ce procédé donne accès à des composants tolérant des défauts de mise au point extrêmes (Ψ≈±100 radians , après filtrage). La dernière partie présente une validation expérimentale de l’instrument dans différents régimes, et à différentes échelles. Il a notamment été mis en œuvre sur l’installation LULI2000, où il a permis de mesurer dynamiquement la déformation et la fragmentation d’un matériau à base de carbone (champs millimétriques). Nous présentons également les mesures obtenues sous sollicitation pyrotechnique sur un revêtement de cuivre cylindrique de dimensions décimétriques. L’apparition et la croissance rapide de déformations radiales submillimétriques est mesurée à la surface du revêtement<br>A Structured Light System (SLS) is an efficient means to measure a surface topography, as it features both high accuracy and dense spatial sampling in a strict non-invasive way. For these reasons, it became in the past years a technique of reference. The aim of the PhD is to bring this technique to the field of shock physics. Experiments involving shocks are indeed very specific: they only allow single-shot acquisition of extremely short phenomena occurring under a large range of spatial extensions (from a few mm to decimeters). In order to address these difficulties, we have envisioned the use of a well-known high-speed technique: pulsed laser illumination. The first part of the work deals with the evaluation of the key-parameters that have to be taken into account if one wants to get sharp acquisitions. The extensive study demonstrates that speckle effect and depth of field limitation are of particular importance. In this part, we provide an effective way to smooth speckle in nanosecond regime, leaving 14% of residual contrast. Second part introduces an original projective formulation for object-points reconstruction. This geometric approach is rigorous; it doesn’t involve any weak-perspective assumptions or geometric constraints (like camera-projector crossing of optical axis in object space). From this formulation, a calibration procedure is derived; we demonstrate that calibrating any structured-light system can be done by extending the Direct Linear Transformation (DLT) photogrammetric approach to SLS. Finally, we demonstrate that reconstruction uncertainties can be derived from the proposed model in an a priori manner; the accuracy of the reconstruction depends both on the configuration of the instrument and on the object shape itself. We finally introduce a procedure for optimizing the configuration of the instrument in order to lower the uncertainties for a given object. Since depth of field puts a limitation on the lowest measurable field extension, the third part focuses on extending it through pupil coding. We present an original way of designing phase components, based on criteria and metrics defined in Fourier space. The design of a binary annular phase mask is exhibited theoretically and experimentally. This one tolerates a defocus as high as Ψ≥±40 radians, without the need for image processing. We also demonstrate that masks designed with our method can restore extremely high defoci (Ψ≈±100 radians) after processing, hence extending depth of focus by amounts unseen yet. Finally, the fourth part exhibits experimental measurements obtained with the setup in different high-speed regimes and for different scales. It was embedded on LULI2000 high energy laser facility, and allowed measurements of the deformation and dynamic fragmentation of a sample of carbon. Finally, sub-millimetric deformations measured in ultra-high speed regime, on a cylinder of copper under pyrotechnic solicitation are presented
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Mau, Adrien. "Développements pour l'imagerie quantitative et à haut contenu en microscopie de fluorescence classique et super-résolue." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASP016.
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La microscopie de fluorescence et la microscopie de localisation de molécules uniques (SMLM) permettent d’imager spécifiquement les entités subcellulaires et sont donc des outils indispensables en Biologie. Cependant ces techniques d’imagerie sont intimement liées aux propriétés de l’illumination, qui possède des limites en termes d’uniformité et de contrôle de l’éclairement.Nous proposons une nouvelle méthode d’illumination nommée ASTER (Adaptable Scanning for Tunable Excitation Regions), capable de délivrer une illumination modulable et uniforme, et compatible avec les méthodes de sectionnement optique classiques. Nous l’appliquons en premier lieu à la microscopie de fluorescence où nous montrons sa compatibilité avec l’imagerie d’échantillons vivants. Ensuite, dans le contexte de l’imagerie SMLM nous démontrons l’obtention de résolutions uniformes, mais également l’impact sur d’autres paramètres et possibilités d’acquisitions. Ainsi ASTER permet de réduire le fond ambiant, d’imager des champs larges de 200x200µm² ou de réaliser une image SMLM sur l’ordre de quelques minutes.Nous présentons ensuite le bénéfice du couplage d’ASTER avec l’imagerie 3D, et une méthode d’imagerie multi-couleur SMLM. Cette méthode quantifiée analytiquement permet d’obtenir des cross talk de l’ordre de 2%, nous montrons sont application à l’imagerie à deux et trois couleurs, ainsi qu’à l’imagerie 3D. Différentes pistes d’amélioration d’ASTER et de l’imagerie multi couleur sont ensuite proposées<br>Fluorescence and Single Molecule Localization Microscopy (SMLM) allows for thespecific labeling and imaging of biological samples, and are an essential tool for biologists.However, images are generally non-quantitative and limited in feld of view, as well as in imagingtimes. These limits are fundamentally linked to the illumination scheme, which should be optimized both in term of uniformity, but also in control of the irradiance. We propose a novelillumination scheme named ASTER, which allow for a versatile and uniform illumination and is compatible with classical optical sectioning schemes. We first apply ASTER to fluorescence microscopy and particularly the imaging of live dynamic samples. Then we show the ability toobtain uniform resolution in SMLM, as well as the potential of ASTER's versatility. One mayreduce the uorescent background, image wide200 x 200 µm² fields, or realize a SMLM image under a minute. Finally, we present theimplementation of a multicolor SMLM experiment, allowing for the simultaneous imaging ofdifferent structures with cross-talks around 2%.This method is quanti ed and optimized, andthen applied to two and three color imaging, aswell as 3D imaging. Different perspectives for ASTER and multicolor imaging are then proposed
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Chang-Chien, Ching-Ho, and 張簡靖禾. "RGB Laser for Special Illumination Applications." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/4axeum.
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碩士<br>國立高雄應用科技大學<br>光電與通訊工程研究所<br>101<br>Common light sources available in the market include incandescent bulbs, fluorescent lamps, mercury lamps, halogen lamps, LED lamps. Recently LED light sources and related applications are especially developed rapidly. For short-range illumination, LEDs incorporated with specially designed lampshades are required. For medical applications, a short range illuminator is required to light a small area. In such cases, LEDs connected to optical fibers seems to be the promising candidate. However during the lightwave propagating in the system, poor performance both in uniformity and brightness are found due to large divergence angle of the LEDs and high coupling losses between the two optical components. In this paper, a laser system incorporated with a diffusion film can greatly reduce the coupling losses and the uniformity problem is improved as well.
In this paper, a CW laser system with red, green, and blue is employed as the white light source, suitable to short-range and small-area applications. The chromaticity coordinates of the system calculated is (0.240, 0.262). By using laser projector as a light source incorporated with imaging system, the optical fibers with various core size are arranged to increase the illumination area and the maximum illumination angle is 37°. A CMOS camera system is used to test the visible area of the illumination system and the maximum visible angle is 45°. The system has a brightness of 0.009 lumens. From the Calculation of the standard deviation of output power, the laser system with a diffusion film is observed to improve the uniformity and the brightness of the output optical power.
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Shu, Chun-Wei, and 蘇峻緯. "Influence of Excimer laser illumination on micromachining." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/99081037468089230066.
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碩士<br>國立成功大學<br>機械工程學系碩博士班<br>92<br>Abstract
The purpose of this research is to examine the influence of excimer laser illumination on micromachining. Here are three different kinds of condition that influence light distribution. First, the incline of work piece and the laser beam indicates that the ablation rate decreases with the increase of incident angle for various influences. Beside, the depth of a hole in the samples oblique to the laser beam at a distance from the focal plane decreases with the increase of the distance from the focal plane. Second, to increase the lens on the path of rays will change the light projection area. According to the situation, the change of energy density causes the change of ablation rate. In this case, it will present the experimental and simulation results. The theory of the model can divide into two steps. In the beginning, the local distribution of the light over the developing structure is evaluated for each pulse by using Fourier optics. Then, the local distribution is used to calculate the local etch rate, and hence the change to structure. Finally, the defocus of the laser beam changes the local light distribution. When the degree of the defocus increases, the beam’s intensity becomes not uniform. The result of simulation shows that the defocus increases, then the structure becomes U-grooves.
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Liu, Yu-Hsuan, and 劉宇軒. "Quantization of Laser Speckle's Impact on Image Resolution of Direct Laser Illumination Systems and Laser Scanning Illumination System's Exceptional Performance on This Topic." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/j47y78.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>106<br>The high coherence characteristics of the laser light itself cause a laser speckle phenomenon in the image received by the laser range-gated system. This phenomenon undoubtedly reduces the image quality and affects the sharpness and naturalness when the observer viewing things.
Therefore, this dissertation proposes a mathematical quantitative model between laser speckle size and image resolution. This mathematical model is capable of quantifying the size of the laser speckle formed by a laser range-gated system using different methods of suppressing laser speckle phenomena. The new invention patent technology replaces the illumination source of the existing laser range-gated system. Calculated laser range-gated system, the size of the laser speckle formed on the detector. Finally, the different methods of suppressing laser speckle is simulated by a laser range-gated system. It is proposed that reducing the size of the laser speckle will increase the image resolution of the detector and the detection distance of the laser range-gated system.
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Chen, Kuan-Ting, and 陳冠廷. "Calculation of Speckle Contrast of Direct Laser Illumination Systems and the Laser Scanning Illumination System's Exceptional Performance on This Issue." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/py2rr7.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>106<br>Laser light has the following characteristics compared to other light sources：（1）Directionality（2）Monochromaticity（3）Coherence. Because of these characteristics, laser light plays an important role in many fields. For some specific illumination applications, it is more suitable to use laser light as the illumination source. However, the high coherence characteristic will cause laser speckle phenomenon when using a laser light as an illumination source. This phenomenon undoubtedly reduces the image quality and affects the sharpness and naturalness when the observer viewing things. Therefore, how to design a system that is miniature and low-cost but has high efficiency to suppress or even eliminate the phenomenon of laser speckle is an important issue that needs urgent efforts.
In order to achieve the above purpose, Professor Chih-Hsiao Chen of National Taiwan University of Science and Technology proposed an invention patent [23]. The invention patent utilizes a MEMS scanner as a drive engine for the phase of the laser light changing over time. By this mechanism, statistically independent speckle patterns are generated, thereby effectively suppressing the laser speckle phenomenon. The purpose of this dissertation is to establish a mathematical model and use MATLAB software to simulate and quantify the ability of the invention patent to suppress laser speckle. To further refine the invention patent by quantitative analysis. According to the simulation results, the system proposed by the invention patent suppresses the laser speckle phenomenon to 2 %. The ability of the laser scanning illumination system to suppress laser speckle phenomenon is evident.
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Chen, Kuan-Yu, and 陳冠宇. "Fabrication of Blue-Laser Benzocyclobutene Optical Waveguide by UV Illumination." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/88066761879793360293.
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碩士<br>國立臺灣大學<br>光電工程學研究所<br>94<br>In this work, buried-type single-mode benzocyclobutene (BCB) channel waveguides fabricated by 248nm krypton fluorine (KrF) excimer laser for a blue laser of wavelength 473nm are first demonstrated. The ultraviolet-induced refractive index changes, measured by prism coupler and spectroscopic ellipsometer, are dependent on the number of laser shots and the pulse repetition rate. By arranging the number of laser shots and the mask width, mode sizes with different aspect ratios can be obtained. Moreover, the proposed UV illumination method is much simpler and more flexible than the conventional dry etching method.
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Chang, Yu-Shuan, and 張宇萱. "Fabrication of Benzocyclobutene Multimode Interference Devices by Ultraviolet Laser Illumination." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/46453448588527043607.
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碩士<br>國立臺灣大學<br>光電工程學研究所<br>96<br>Buried-type benzocyclobutene (BCB) multimode interference (MMI) optical power splitters fabricated by the ultraviolet laser illumination are presented. The devices of interest are 1 4, 2 2, and 4 4 MMI devices. The BCB polymer is illuminated by 248nm krypton fluorine excimer pulse laser through a quartz mask. The single mode waveguide has width of 7μm and refractive index of 0.0027 to 0.003. The best 1 4 MMI device exhibits a transmission of 95.52% and an imbalance of 0.41dB with interaction length of 1520μm. The best 2 2 MMI device exhibits a transmission of 92.96% and an imbalance of 0.08dB with interaction length of 1900μm. The best 4 4 MMI device has an interaction length of 8400μm, which exhibits a transmission of 86.87% and an imbalance of 0.84dB when light is input from the outer access waveguides, and a transmission of 82.34% and an imbalance of 0.4dB when light is input from the inner access waveguides. Without the problem of side-wall roughness, BCB MMI devices fabricated by ultraviolet laser illumination exhibit smaller insertion loss as compared with those by other polymer and process. Experimental results, which agree quite well with the simulated results, show the BCB MMI power splitters can be fabricated with good controllability, high accuracy, and short time.
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Yi-ChengWang and 王以誠. "Darkfield illumination with laser beam shaping for Raman detection of particles." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/t6nctq.
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碩士<br>國立成功大學<br>光電科學與工程學系<br>105<br>We attempt to measure the Raman signals of a single particle through the setup of darkfield microscopy. The darkfield microscopy setup has an annular aperture, which can block central region of the incident light and create an annular beam. In this setup, the annular beam can illuminate the specimen obliquely. At an oblique angle illuminating specimen can reduce the scattering signals of the substrate collected by the objective, but the scattering signals of the specimen are still captured by the objective. In the darkfield setup, the scattering signal intensity ratio between the substrate and specimen will be closer. In order to measure the Raman signals, the He-Ne laser, whose intensity distribution is Gaussian, is used as the illumination light source, so the intensity of the laser beam will be blocked by the annular aperture in the darkfield setup. To overcome this problem, Axicon, an optical lens with a conical surface, is used to transform the shape of the Gaussian beam into a crescent shaped beam. The crescent shaped beam can pass through the annular aperture and reduce the loss of the intensity. The crescent shaped beam is used as the illuminating light source in the darkfield setup to measure the Raman signal of a single polystyrene (PS) particle on the silicon substrate. We expect the Raman signals from the silicon substrate will be reduce in darkfield setup, so the Raman signal intensity ratio between the particle and the substrate will be closer.
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Li, Chien-Te, and 李建德. "Reflector Design and its application to IR illumination and Laser Speckle Reduction." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/46440661058693232675.
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碩士<br>國立交通大學<br>光電工程系所<br>95<br>In this thesis, we consider the optical designs of reflector in a variety of illumination application, namely, infrared illumination and laser speckle reduction. In the application of IR illumination, Nucleic-acid analysis using PCR is one of the indispensable and powerful methods used in the areas of molecular and clinical diagnostics and forensic applications. Due to a great demand for miniaturized portable real-time PCR based point-of-care devices, a non-contact thermo-cycling approach using IR system is popularly employed. We explored such an IR illumination system; we simulate a tungsten halogen lamp for light source, and investigate the optical performances of typical parabolic and developed faceted trough-type reflectors with 9x6 cm2 illumination target. It is shown that a promotion of luminaire efficiency 19.6% and the uniformity with 25 mm2 sub regions achieving up to 96% can be done by using designed faceted trough reflector.
For the application of speckle reduction, rapid advances in mini-projector provide us to project multimedia data at anytime anywhere with the help of portable communication device such like mobile phone and PDA. Utilizing laser diode with its high intensity, low electrical power consumption, small volume and excellent color performance, it has a good potential for illumination source of mini-projector, except that it has good coherence which results in speckle effect and will decrease its image quality. We report a laser speckle reduction method using integrating sphere which reduce speckle contrast to 8.99% and design the optical system of reflector to collimate laser beam for the illumination of projection displays(divergence angle is lower than 3 degree).
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Lu, Eugene Youjhen, and 盧宥蓁. "The ROS induced by laser illumination and its effect on cell migration." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/66548515169039697065.
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碩士<br>國立陽明大學<br>生醫光電研究所<br>102<br>We project a 473 nm and a 660 nm laser light pattern onto the cell adhesion surface to modulate cell migration. And we investigate the role of reactive oxygen species (ROS) in the mechanism of how blue light induces cell migration behavior.
A spatial light modulator(SLM) is used to generate 473 nm and 660 nm laser pattern imaged onto the stage of a microscope. This system was created by Dr. Jian-Long, Xiao. Through this system, our group have demonstrated that 473 nm laser light pattern can be used to culture cell into arbitrary shapes of cell sheets, or push cell move forward. We also used 473 nm laser pattern as a tool to study collective migration of lung cancer cells CL1-5.
Compared to other methods such as micro fluidic systems, using light to create channels to study cell migration provides a better temporal and spatial resolution. For example, we can easily change the shape of optical channels at any time. However, the mechanism of optical modulation on cell migration is still unclear. From the report of other groups, we know that ROS play an important role when cells are damaged by blue light. And ROS is also related to cell migration in respond to environmental cues.
We use ROS indicator (CM-H2DCFDA) to label cellular ROS when A549 cell is illuminated by a 473 nm and 660 nm laser pattern. The result shows that the ROS level induced by the 473 nm illumination has a dose dependency on the illumination intensity, but not in the 660 nm case. We also found that cell can sense a sharp intensity gradient of 473 / 660 nm laser and migrate to the dark/ bright side. Finally, we found that the ROS has no special distribution in a single cell, which suggest that CM-H2DCFDA labeled ROS is not involved in 473 nm laser induced cell migration.
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Kuo, Chen Nan, and 郭陳年. "Imaging photofragments in velocity space by laser sheet illumination techniques: Photodissociation of ICN." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/45403959696989687224.
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博士<br>國立中山大學<br>化學學系<br>82<br>Combining laser sheet illumination and two-dimensional image
techniques, photofragmentation of ICN at 248 nm was studied in
great details. The three-dimensional distribution of number
density, angle and velocity of state-selected CN photofragments
was successfully determined by slicing an expanding, spherical
shell from the photodissociation center sequentially. A
physical model was developed to correlate the photodissociation
dynamics and image patterns from this direct method. Slicing
an expanding Newton sphere of state- selected photofragments by
the pulsed laser sheet at various delay times relative to the
photolysis event, we simulated numerically the resultant image
frames in velocity space. To accommodate realistic experimental
conditions, intensity patterns which take into account
contributions from internal energy and velocity distributions
of precursors and an assembly of photolysis centers on an arc
were presented. In the framework of the imaging model, time-
resolved image patterns from photofragmentation of ICN were
employed to illustrate the influence of internal energy and
velocity distributions of precursors.
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Yi, Po-Wei, and 易柏維. "Using varying length of fiber bundle to reduce the laser speckle of endoscope illumination source." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/s9u85x.
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碩士<br>國立陽明大學<br>生醫光電研究所<br>107<br>In order to not only reduce the section of endoscope but also maintain sufficient brightness. We utilize a high coherent semiconductor laser as the light source. But it also accompanies speckle generation. When the high coherent light source transmitts to the screen or the object, the surface of the object is not smooth, resulting in the scattered light to interfere, which affects the image quality. Therefore, reducing the speckle to enhance image clarity is the goal of the experiment.
We use customized fiber, buzzer, and laser speckle reducer to lower speckle contrast. The customized fiber is made by fiber bundle. Each fiber with different lengths. The difference of length is a multiple of the coherence length of the laser light. These three methods the change the mode of the light transmission, thereby reducing the coherent of the laser source. Due to reduce the coherent of the light source, reducing the generation of the speckle. And analysis the image obtained by each method by signal-to-noise ratio and flatness.
The result show that the customized fiber obtains the best speckle removal and the most uniform image. Compared to the high speckle contrast image from using single fiber. This method can observe the object clearly. But when we introduce the two fibers into the otoscope, it’s almost without speckle pattern in the image. Base on this reason, we speculate that the special fiber bundle can reduce the spot contrast should be the difference in spatial distribution instead of temporal delay. As the otoscope is the fiber bundle with same length of each fiber. Fibers split one source into multiple light source. Each light source may generate speckle pattern. According to the superposition of all speckle, the spot contrast is lower.
Customized fiber, without noise, and more convenient than laser speckle reducer. It can be applied to ultra-slim endoscope developed by us. The application not only provides sufficient brightness but also reduces the problem of speckle. It has the potential to develop into a commodity by improving the stability.
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Chao, Weng Sun, and 趙文山. "Laser Illumination effects on the Surface Morphology and Surface -Enhanced Raman Scattering of Water Molecules on Ag Electrodes." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/14904513646183797294.
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Ho, Ching-Ju, and 何靜茹. "Development of a new type optical CT scanner by using a collimated single laser line with uniform flat-top illumination." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33270657835254850957.
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碩士<br>國立臺北教育大學<br>自然科學教育學系碩士班<br>98<br>ABSTRACT
As radiation therapy technology advances, measurements of 1-D and 2-D dose distributions are insufficient to meet the clinical requirements. 3-D dose distributions of gel dosimeter has been widely developed and emphasized to replace traditional technique. The purpose of this study is to establish an optical scanner via parallel laser source system to read 3-D dose distributions.
This work exploited a solid-state laser line projector with uniform flat-top illumination from Stocker Yale, coupled with two spherical lens to redistribute the 90 degree sector-shaped laser source into a collimated light. Stepper motors controlled the vertical translations and rotations of the gel cylinder and the scanning data was recorded by a CCD camera.
A collimated laser was utilized as the light source of optical scanner in the experiment so that only vertical translations and rotations but the horizontal translations are required for cylinder-shaped gel dosimeter to complete a 3-D scan. However, the line width of the system is only 20mm, which cannot be a referenced light intensity signal in real time to assemble and reconstruct the scanning information. Hence, this work focuses on the analysis of parallelism, stability, and spatial intensity distribution of the collimated laser light source. Results show that the width of the collimated light source is 20mm, the parallelism of the light source is less than 0.045 degree, the spatial intensity distribution ranges between 14.1%~15.7%, and the repeatability of the intensity distribution of light is within 4.8%.
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Chou, Yao-Chun, and 周曜群. "The Effects of High-Temperature Treatment and Persisted Laser Illumination on the Surface Enhanced Raman Scattering of Benzoic Acid by Silver-Doped Sol-Gels." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/70536724250581209937.
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碩士<br>逢甲大學<br>光電研究所<br>96<br>This thesis deals with the surface enhanced Raman scattering (SERS) of benzoic acid’s ring breathing mode (1003cm-1) and carboxyl C=O vibrational mode (1600cm-1) by the silver particles doped sol-gels with various high-temperature treatments and persisted laser illuminations. The sol-gels are made out of tetramethyl orthosilicate (TMOS), water, methanol, and formamide with the molar ratio of 1:4:4:2. Methanol is chosen as the solvent of the benzoic acid (BA) solutions for its immunity to the SERS effect. Consequently, methanol’s 1033cm-1-peak can serve as a good internal reference for the normalization of the spectrum intensity. The concentration of BA solution is diluted to 10-2 M to ensure that only SERS of BA are detected and the normal Raman scattering of BA can be neglected.
Referring to the boiling points of sol-gel’s compositions and the glass transition temperature, ten different heat treatment temperatures ranging from room temperature to 900℃ are chosen. The experimental results indicate that BA SERS intensity first rises and than drops with the increase of sol-gel’s heat-treatment temperature. However, over the period of 5 hours’ persisted illumination by 37.5mW laser, different heat-treated sol-gels exhibit quite different trends of the SERS intensities. It seems that sol-gels heat-treated at around 600℃ have the good SERS performance in terms of intensity and stabilization. These complicated SERS trends are not only attributed to the variations of porous networks but also related to the flow of trapped organics, the thermodynamic equilibrium processes, structural changes and carbonizations caused by the laser’s local-heat effect. The detail analysis is discussed in this thesis.
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Li, Meng-Che, and 李孟哲. "Micro DLP Projector with Laser Illuminator." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/90796414238543037474.
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碩士<br>國立清華大學<br>動力機械工程學系<br>97<br>Abstract
The rapid evolution of digital projector technology in the recent years, one of the major trends is light, thin, and small portable projector. The research is an extended work based on Texas Instruments Inc. DLP (Digital Light Processing) projection technology which discusses the feasibility on how to shrink optical system in non-imaging and imaging optical designs. Another key feature is exploiting laser instead of conventional UHP lamp as the illuminator.
During the experiment, the prototype is modified from an existing commercial DLP projector bought from the projector market. The laser projector should be able to project image on the wall after the modification. The article will describe the detail process of the integration including optical simulation to design a small achromat doublet projection lens, laser illuminator design, laser beam shaping, and electronic controller design to control lasers in color-sequential mode. Eventually, evaluate the each performance index after the laser projector is successfully in operation.
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Ho, Ya-chieh, and 何雅潔. "High-Efficiency Two-Layer Coupler Design for Natural Light Illumination System." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/64247980869431065455.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>102<br>Nowadays, global warming has become a major issue. Reducing the consumption of fossil fuel and saving energy were the top priorities. In response to the energy crisis, renewable energy has been widely taken as other energy options. Solar energy is one of the most essential and abundant energy. If we can collect and transmit natural light into buildings without opto-electronic conversion, that will save energy and provide healthier light into our daily life. Therefore, our team designed a series of products known as Natural Light Illumination System (NLIS). In developing the high-quality NLIS, our primary concern was to increase the efficiency of the system. When the concentrators in daylight system collects sunlight, the light transmits through light pipe or fiber to any room you want. However, the efficiency decreases dramatically as the number of concentrator increases, due to the interconnection parts which encounter huge loss.
For high-efficiency light transmission, the paper presents a design of coupler which assembles concentrators in module. The coupler consists of two structures, convergent element and light guide. According to the candle power distribution curve of the concentrator, we created the convergent element with multi-stage curvature. The concept of the multi-stage curvature is similar to the spherical surface which can compress sunlight smaller. Furthermore, the light guide gathered all light from concentrators and guided to the single exit port, which reduced the number of transmitting component. The module with coupler improved 23.29 % in efficiency with the same collecting area, which was 2.68 times higher. Furthermore, the lower transmitting components were not only lower cost and area but also easy to set up in the building or any place you want.
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Lugongolo, Masixole Yvonne. "Optical micro-manipulation in HIV-1 infected cells for improved HIV-1 treatment and diagnosis." Thesis, 2020. http://hdl.handle.net/10500/26551.
Full textAbstract:
Laser application in the field of biological and medical sciences has significantly grown, thereby
strengthening the field of Biophotonics. Research conducted in Biophotonics focuses on the concept
of using light especially in the visible and near infrared regions of the electromagnetic radiation for
the evaluation of living systems. In this thesis new discoveries are presented about low level laser
therapy, optical trapping, transmission spectroscopy, luminescence spectroscopy and structured
illumination microscopy (SIM), displaying the impact each technique has on HIV infected cells. The
results showed that the irradiation of HIV-1 infected TZM-bl cells with low power red laser reduces
HIV-1 infection. The outcomes of this study further proved that when irradiation is used in
conjunction with efavirenz, an antiretroviral drug, HIV-1 infection could be reduced to undetectable
levels in TZM-bl cells. Through the coupling of transmission spectroscopy with optical trapping, and
separately, use of luminescence spectroscopy, label free diagnosis of HIV in infected cell samples
was achieved. This finding affirms that HIV-1 infection can be detected in a label free manner when
using laser based techniques. Furthermore, the photoluminescence spectrometer system was
employed to generate a decay curve, which was necessary so as to have some understanding on
lifetime of the luminescent signal in infected TZM-bl cells. Finally, in order to confirm that indeed
TZM-bl cells were infected, an established super-resolution microscopy system SIM was used to
detect HIV-1 infection in TZM-bl cells. Indeed in the infected cells viral molecules p24 and gp41
were detected through SIM, while they were not detected in uninfected cells. In future studies, super
resolution microscopy would be coupled to an optical trapping system in order to confirm that each
trapped cells is whether infected or uninfected so as to improve HIV diagnosis.<br>College of Science, Engineering and Technology<br>Ph. D. (Science, Engineering and Technology)
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Wang, Yu-sheng, and 王昱升. "Optoelectronic behaviors of n-ZnO/i-Al2O3/p-Si diodes under high-power-laser illuminations." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/jp83re.
Full textAbstract:
碩士<br>國立中山大學<br>物理學系研究所<br>103<br>In this thesis work, pin-diodes made of p-Si/AlOx/c-ZnO were investigated in regards to their photo-responses to high-power Nd:YAG laser of wavelength = 1064nm and that at 532nm via second-harmonic generation, both operated at various optical power levels. The diodes exhibit large leakage current as they were made, suspected to be a combined result of domain-boundary conduction paths within ZnO, as they are a layer of thin films textured along the c-axis in general, followed by tunneling of carriers across the insulating AlOx layer. Such as-fabricated diodes, characteristic leakage disregarded, demonstrated backward-diode behaviors, essentially a manifestation of a tunneling diode in which the carriers tunnel from one side to the other under an external electric field, whether illuminated or not. The sophisticated IV curves are analyzed as related to the abundant defect-related gap states that obscure the expected forbidden voltage regions of tunneling that are characteristic of the energy gaps of the two constituent semiconductors. Attempts were made to infer the basic semiconductor properties, such as the associated hetero-junction heights, Fermi level positions, among others, from quantitative analysis of the IV curves under illuminations or without. The backward diodes were then annealed at various high temperatures, intended to annihilate a part of the inherent defects, and were then characterized in similar procedures. After annealing, the tunneling characteristics of backward diodes diminished, replaced by slightly leaky regular diode or pin-diode characteristics. Very weak sign of photovoltaic response, if any, could be identified. A circuit model is proposed to account for the observed photoconduction behaviors and their correlations with the processes of the device fabrications are discussed.
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Tsai, Min-Yen, and 蔡旻諺. "Applications of UV shield layer for negative-bias-illumination-stress instability in a-InGaZnO TFTs." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/34320712582064361713.
Full textAbstract:
碩士<br>國立交通大學<br>顯示科技研究所<br>102<br>The electrical characteristics of a-IGZO TFTs affected by ambient environment, including oxygen, moisture, and light illumination, are still among the issues for a-IGZO TFTs to be the commercialization of for flat panels. Passivation layers, e.g. SiO2 or SiNX, on an active layer are an effective method to improve the oxygen or moisture effects. However, the photosensitivity issue still occurs in a-IGZO TFTs by introducing above mentioned passivation layers. A transparent metal oxide semiconductor: Mo-doped ZnO (MZO) with UV shielding ability as the passivation layer to improve the photosensitivity issue of a-IGZO TFTs is proposed. Results reveal that MZO-passivated a-IGZO TFTs remain the stable properties during NBIS tests, while the transfer curves of unpassivated and SiO2-passivated a-IGZO TFTs have apparent negative shifts during NBIS tests. Moreover, during PBS and NBS tests, MZO passivation layer presents the similar protective ability under ambient environment to SiO2 passivation layer. Hence, MZO passivation layer shows high potential to be used in next generation displays.
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Ma, Chi-tang, and 馬啟唐. "Design of Static Solar Concentrator with Interlaced Double-Layer Lens Arrays for Natural Light Illumination System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/2a9rq4.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>99<br>In recent years, due to the awareness of environmental protection, the use of green energy gets more and more attention around the world. Industry and academia focus on the use of sunlight to provide indoor lighting and save energy.
One of the structures of solar concentrator is using lens to collect light, which features a high concentration ratio. But the acceptance of incident light angle of lens-type concentrator is quite small. If there is a tilted angle θ between parallel light and optical axis of lens, the focal point shifts from the original position and cannot be guided to light pipe. So the lens-type concentrator usually goes with dynamic sun tracking system to make the optical axis of lens parallel sunlight.
Therefore, we propose a novel static solar concentrator without high-cost sun tracking system, which contains collection and transmission parts; the collection part is the array of interlaced two-layer lenses in semi-circular arrangement and two-layer lenses comprise the first-layer lens at the top and the second-layer lens at the bottom; the transmission part is one acrylic light pipe. Furthermore, we optimize the aspheric coefficients of lens. Each first and second-layer lens is responsible for collecting sunlight at corresponding time. So sunlight with different incident angles in daytime passes through two-layer lenses that refracted to light pipe effectively.
We simulate the concentrating performance of the concentrator and only light pipe under real solar radiation in the summer solstice, vernal equinox, and winter solstice in Taipei city, Taiwan. According to the simulation results, the concentrator in this paper can provide steady luminous flux in daytime for kinds of lighting application.
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Hsieh, Chih-Hao, and 謝志豪. "Nearly White Light Illumination from a GaN-Based Light Emitting Diode Integrated with a Porous SiO2 Layer." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/35634460086978286387.
Full textAbstract:
碩士<br>國立臺灣大學<br>光電工程學研究所<br>94<br>In this research, we develop a nearly white light emitting device by integrating blue/green emission from a GaN based light emitting diode (LED) with red emission from a porous SiO2 layer. The porous SiO2 layer was fabricated by a novel process procedure to create Si nanocrystals on top of the n-type GaN layer. Red light is generated from the metal-oxide-semiconductor (Ni/Au–SiO2 oxide-n-type GaN) structure due to the electron-hole recombination in the Si nanocrystals. The device shows a blue light emission at a low biased voltage and nearly white light emission (green and red colors) at a bias voltage between 14V and 16V. Our results show the potential of applying such an integrated structure to white light illumination.
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Mason, Ashley D. "Effects of ultraviolet illumination and a parylene-A activation layer on the gas phase sensing characteristics of ZnO nanobridges." Thesis, 2011. http://hdl.handle.net/1957/21925.
Full textAbstract:
ZnO nanowires (NWs) are good candidates for chemical sensing because of their high surface-to-volume ratio. In this work, ZnO nanobridge sensors were fabricated utilizing a novel method which uses carbonized photoresist (C-PR) as a nucleation layer. The use of C-PR allows simultaneous growth and integration of NWs to lithographically-defined features. The nanobridge sensors are shown to be sensitive to the presence of O₂, H₂O, CO, and H₂/N₂ gas. However, since ZnO dissolves in water, a protective layer is necessary for these sensors to be used in the liquid or vapor phase. A chemical vapor deposition (CVD) process for amino-[2,2]paracyclophane (parylene-A) was developed and used to successfully protect the NWs. Gas sensing measurements were performed on bare and parylene-A coated devices with and without UV illumination. The parylene-A layer was found to attenuate sensitivity to O₂ and H₂O, and UV illumination was found to decrease the response time.<br>Graduation date: 2012
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Yu-RuLin and 林育如. "Improvement of Light Illumination Efficiency of GaN-based LED by Co-Sputtering Multi-layer Graded-index ZnxSiyO3 Thin Film." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/83004557759894234853.
Full textAbstract:
碩士<br>國立成功大學<br>光電科學與工程研究所<br>98<br>In this study, we prepared the different refractive index of ZnO-SiO2 compound thin films by changing the contents of ZnO and SiO?2. First, we used ray-tracing simulation to study the light extraction efficiency of graded-index films stacked on GaN-based LEDs. And then, we implemented the similar structures on GaN-based LEDs to improve the light output power efficiency.
In this experiment, ZnO-SiO2 compound thin films were prepared by co-sputtering, and these kind of compound thin films are defined as ZnxSiyO3. The co-sputtering ZnxSiyO3 thin films indicated high transmittance over 90% around 460nm. The cut-off wavelength of ZnxSiyO3 thin films have blue shift with the Si content increased. Meanwhile, the refractive index was on the decrease. Therefore, the refractive index of ZnxSiyO3 could be varied between 1.46 for pure SiO2 to 2.1 for pure ZnO.
We have demonstrated graded-index ZnxSiyO3 thin films on p-type GaN-based LEDs. The 20mA-forward voltage was varied from 3.06V to 3.17V and 3.19V for LED with plane-ITO, LEDs with two layers and three layers graded-index film inside the circle-hole mesh mesh-ITO, respectively. The 20mA-output power were 4.73mW, 5.19mW and 5.31mW for LED with plane-ITO, LEDs with two layers and three layers graded-index film inside circle mesh-ITO. As our experimental results, we could understand the loss elimination between two layers could be achieved by graded-index thin film.
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Chen, Yen-Chiao, and 陳彥橋. "Utilizing the Nb2O5 blocking layer to improve the power conversion efficiency of dye-sensitized solar cell under indoor light illumination." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/58665991686015563282.
Full textAbstract:
碩士<br>國立中興大學<br>化學工程學系所<br>105<br>In 1991, Michael Grätzel has invented the dye-sensitized solar cells (DSSCs) which the efficiency of the solar cells reaches 7 % under 1 sun condition. The DSSCs have many advantages of low cost, environment protection and easy fabrication. DSSCs are limited by the recombination reaction of the electrons from the fluorine-doped tin oxide (FTO) substrate back into the electrolyte and from the TiO2 to electrolyte. In order to suppress the electron recombination at the FTO/electrolyte interface, the Nb2O5 blocking layer which can prevent the electrolyte from direct contact with the FTO substrate is deposited on the FTO to improve the DSSCs performance. The FTO is dipped into NbCl5 ethanol solution for 30 s at room temperature to form Nb2O5 blocking layer after annealing. In transmission electron microscope (TEM) images, the thickness of Nb2O5 blocking layer is about 14 nm through three times dipping cycles. By atomic force microscope (AFM) and scanning electron microscope (SEM) analysis, the surface roughness of FTO decreases with increasing the dipping cycles because Nb2O5 layer forms onto FTO crystal defeat. To make sure the layer composition, the signal of Nb5+ is detected by X-ray photoelectron spectroscopy (XPS) result. Based on the analysis results of transmission line model and electrochemical impedance spectroscopy (EIS), the blocking layer can promote the DSSCs power conversion efficiency (PCE) by increasing the electron recombination resistance and reducing the series resistance. The suppression effect becomes obvious as increasing dipping cycles but a thick blocking layer can resist the illumination income and lower the short circuit current. In other word, the blocking layer has the optimum thickness to enhance the photovoltaic performance and plays a more important role in the indoor or low intensity lighting applications.
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Kemp, Jamie. "The Mind's Eye: Visualizing Encyclopedic Knowledge in the Later Middle Ages." Thesis, 2014. http://hdl.handle.net/1828/5773.
Full textAbstract:
This dissertation critiques and updates the theoretical frameworks for understanding encyclopedic and diagrammatic images as presented in the scholarship of Lucy Freeman Sandler, Barbara Maria Stafford, John Bender, and Michael Marrinan. It offers a new model for examining the cognitive role of images by studying an important medieval encyclopedia, On the Properties of Things, originally written in Latin by Bartholomaeus Anglicus in the thirteenth century.
Bartholomaeus’ text was the most popular encyclopedia of the later middle ages and four vernacular translations were produced and circulated between the fourteenth and sixteenth centuries. Significantly, the French translation of the compendium, coming out of the vernacularization movement of King Charles V but radiating out to other production centres, involved the design of an elaborate and novel illustrative program. The present project examines two exceptional fifteenth-century French copies of this encyclopedia (BnF fr. 9141 and BnF fr. 135/6), and interprets them in light of the shifting intellectual culture and evolving reading practices of late-medieval lay audiences.
The information-rich and highly aestheticized miniatures found in such encyclopedic manuscripts have traditionally been defined, by Sandler and others, as having an explanatory function and the capacity to elevate the content of the text through displays of material luxury. My model expands the significance of such images by highlighting their capacity to promote thought. I argue that images in didactic compendia can (i) encourage the reader to actively engage with the text through representations of aristocratic readers performing their understanding of the book socially, and (ii) facilitate visual thinking by aesthetically reflecting the structure of the encyclopedic text through the diagrammatic strategies of the collection, compression, and division of fragmented information. Though the images in my two manuscript case studies take distinct approaches to reader engagement and the mediation of knowledge, in both cases the power of these visualizations rests in the cognitive acts and range of mental associations they provoke. This dissertation demonstrates that epistemically-dense images, in addition to merely reflecting a text, could shape knowledge as it was being formed in the minds of active viewers, readers, writers, and artists, in an intellectually rich period in late-medieval France.<br>Graduate
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"A Study of Heating and Degradation of Acrylonitrile-Butadiene-Styrene/Polycarbonate Polymer Due to Ultraviolet Lasers Illumination during Localized Pre-Deposition Heating for Fused Filament Fabrication 3D Printing." Master's thesis, 2017. http://hdl.handle.net/2286/R.I.44212.
Full textAbstract:
abstract: With the growing popularity of 3d printing in recreational, research, and commercial enterprises new techniques and processes are being developed to improve the quality of parts created. Even so, the anisotropic properties is still a major hindrance of parts manufactured in this method. The goal is to produce parts that mimic the strength characteristics of a comparable part of the same design and materials created using injection molding. In achieving this goal the production cost can be reduced by eliminating the initial investment needed for the creation of expensive tooling. This initial investment reduction will allow for a wider variant of products in smaller batch runs to be made available. This thesis implements the use of ultraviolet (UV) illumination for an in-process laser local pre-deposition heating (LLPH). By comparing samples with and without the LLPH process it is determined that applied energy that is absorbed by the polymer is converted to an increase in the interlayer temperature, and resulting in an observed increase in tensile strength over the baseline test samples. The increase in interlayer bonding thus can be considered the dominating factor over polymer degradation.<br>Dissertation/Thesis<br>Masters Thesis Engineering 2017