Segui questo link per vedere altri tipi di pubblicazioni sul tema: Optical readout.
Tesi sul tema "Optical readout"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-42 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Optical readout".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
1
Rahman, Rizvi. "Fullerene based systems for optical spin readout". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:e604f0ed-7d3c-44a6-9d97-7c03e7a90580.
Testo completoAbstract (sommario):
Optical spin readout (OSR) in fullerene-based systems has the potential to solve the spin readout and scalability challenges in solid-state quantum information processing. While the rich variety of chemical groups that can be linked (covalently or not) to the fullerenes opens the possibility of making large and controlled arrays of qubits, optical methods can be used to measure EPR down to a single spin thanks to the large energy of optical photons compared to the microwave ones. After reviewing the state of the art of OSR, for which the diamond NV cen- ters constitute the benchmark, we undertake the study of fullerene-based species for OSR. An optically detected magnetic resonance (ODMR) setup was imple- mented in a commercial EPR spectrometer for this purpose. Each experimental chapter focuses on one of the molecular systems in question: a functionalised C60 fullerene with a phosphonate group (C60-phosphine), porphyrin-fullerene ar- chitectures (weakly, strongly and moderately coupled) and finally erbium-doped trimetallic nitride template (TNT) fullerenes (focusing on ErSc2N@C80). In the C60-phosphine system, coherent optically detected magnetic resonance (ODMR) in the triplet state has been achieved. Since a large variety of organic and organometallic molecules can be attached to it both via the fullerene cage and the phosponate group, this result makes it a very useful template to study OSR molecules chemically linked to a qubit. In the porphyrin based structures, an intermediate coupling case in the form of a trimer-fullerene host-guest complex is found to allow detection of both the porphyrin and fullerene triplet sates by CW ODMR, which makes organo-metallic complexes a possible coupling route for a qubit to an OSR component. In the TNT fullerene, crystal field mixing makes the Er3+ inaccessible by ODMR. However, optical photons cause a mechanical rearrangement of the en- dohedral cluster which in turns impacts on the observed EPR. In particular, the dynamics of this process have been studied for the first time and hint to- wards diffusion kinetics at low pump power. An orientational selectivity has been discovered by using a polarised pump, and the time dynamics indicate the rearrangement of the matrix via difusion on a free volume around the fullerenes. This shows that the endohedral Er3+ in ErSc2N@C80 can probe the environment outside the cage.
2
Montagner, Elison. "Optical readout system for bi-material terahertz sensors". Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5478.
Testo completoAbstract (sommario):
Approved for public release; distribution is unlimited.The objective of this work is to design, assemble, and characterize an optical readout for bi-material MEMs sensor arrays that can be integrated into a THz imaging system. All this effort is a contribution to the goals of the research conducted by the Naval Postgraduate School Sensor Research Laboratory on designing and fabricating THz-optimized bi-material MEMs sensor arrays for THz imaging. Basic concepts of THz radiation and detection are presented. Several aspects of THz imaging, and sensor's array readout possibilities, are discussed in terms of the principle of operation for this type of sensor. An experimental optical readout was assembled during this research, and its configuration is shown, as well as all of its component details. The experimental setup was characterized following a method described in this work, and the obtained results are analyzed. Finally, one possibility of optical readout integration with a THz imaging system is suggested.
3
Buseck, David Allan 1963. "High-density CD-ROM readout using direct phase measurement". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276545.
Testo completoAbstract (sommario):
Direct measurement of optical phase is used in a high-density optical disk reader. The increased density is achieved by introducing multiple pit depths to replace the single pit depths of a traditional compact disk. Having four independent pit depths can double the storage capacity of a disk. The multi-level pits are read by direct measurement of the phase difference between two laser spots focused onto the disk surface. Extraction of phase information utilizes the equations of phase shifting interferometry with four shifted fringe patterns created simultaneously by a compact optical head. The system speed is therefore limited by the readout electronics instead of by slow mechanical phase shifters. The resulting system can identify four independent levels as well as the direction of transition from one level to another. The system also has low sensitivity to vibrations and to changes in the fringe contrast and beam intensity.
4
Lee, Wook. "Diffraction-based integrated optical readout for micromachined optomechanical sensors". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-09292006-115918/.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.F. Levent Degertekin, Committee Chair ; David S. Citrin, Committee Member ; Paul E. Hasler, Committee Member ; Peter J. Hesketh, Committee Member ; Zhiping Zhou, Committee Member.
5
Schuldt, Thilo. "An optical readout for the LISA gravitational reference sensor". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16241.
Testo completoAbstract (sommario):
Der weltraumgestützte Gravitationswellendetektor LISA (Laser Interferometer Space Antenna) besteht aus drei identischen Satelliten an Bord derer sich jeweils zwei frei schwebende Testmassen befinden. Die Lage der einzelnen Testmassen in Bezug auf die zugehörige optische Bank muss mit einer Genauigkeit besser 1 pm/sqrt(Hz) in der Abstands- und besser 10 nrad/sqrt(Hz) in der Winkelmessung erfolgen. In der vorliegenden Arbeit wird ein kompaktes optisches Auslesesystem präsentiert, welches als Prototyp für diese Abstands- und Winkelmetrologie dient. Das dafür entwickelte polarisierende Heterodyn-Interferometer mit räumlich getrennten Frequenzen basiert auf einem hoch-symmetrischen Design, bei dem zur optimalen Gleichtakt-Unterdrückung Mess- und Referenzarm die gleiche Polarisation und Frequenz sowie annähernd gleiche optische Pfade haben. Für die Winkelmessung wird die Methode der differentiellen Wellenfrontmessung eingesetzt. In einem ersten Prototyp-Aufbau wird ein Rauschniveau von weniger als 100 pm/sqrt(Hz) in der Translations- und von weniger als 100 nrad/sqrt(Hz) in der Winkelmessung (beides für Frequenzen oberhalb 0.1 Hz) demonstriert. In einem zweiten Prototyp-Aufbau werden zusätzlich eine Intensitätsstabilisierung und ein Phasenlock der beiden Frequenzen implementiert. Die analoge Phasenmessung ist durch eine digitale, FPGA basierte, ersetzt. Mit diesem Aufbau wird ein Rauschen kleiner 5 pm/sqrt(Hz) in der Translationsmessung und kleiner 10 nrad/sqrt(Hz) in der Winkelmessung, beides für Frequenzen größer 0.01 Hz, erreicht. Eine Rausch-Analyse wurde durchgeführt und die Nichtlinearitäten des Interferometers bestimmt. Das Interferometer wurde im Hinblick auf die LISA Mission entwickelt, findet seine Anwendung aber auch bei der Charakterisierung der dimensionalen Stabilität von ultra-stabilen Materialien sowie in der optischen Profilometrie. Die Adaptierung des Interferometers dazu sowie erste Resultate zu beiden Anwendungen werden in dieser Arbeit präsentiert.The space-based gravitational wave detector LISA (Laser Interferometer Space Antenna) consists of three identical satellites. Each satellite accommodates two free-flying proof masses whose distance and tilt with respect to its corresponding optical bench must be measured with at least 1 pm/sqrt(Hz) sensitivity in translation and at least 10 nrad/sqrt(Hz) sensitivity in tilt measurement. In this thesis, a compact optical readout system is presented, which serves as a prototype for the LISA proof mass attitude metrology. We developed a polarizing heterodyne interferometer with spatially separated frequencies. For optimum common mode rejection, it is based on a highly symmetric design, where measurement and reference beam have the same frequency and polarization, and similar optical pathlengths. The method of differential wavefront sensing (DWS) is utilized for the tilt measurement. In a first prototype setup noise levels below 100 pm/sqrt(Hz) in translation and below 100 nrad/sqrt(Hz) in tilt measurement (both for frequencies above 0.1 Hz) are achieved. A second prototype was developed with additional intensity stabilization and phaselock of the two heterodyne frequencies. The analog phase measurement is replaced by a digital one, based on a Field Programmable Gate Array (FPGA). With this setup, noise levels below 5 pm/sqrt(Hz) in translation measurement and below 10 nrad/sqrt(Hz) in tilt measurement, both for frequencies above 0.01Hz, are demonstrated. A noise analysis was carried out and the nonlinearities of the interferometer were measured. The interferometer was developed for the LISA mission, but it also finds its application in characterizing the dimensional stability of ultra-stable materials such as carbon-fiber reinforced plastic (CFRP) and in optical profilometry. The adaptation of the interferometer and first results in both applications are presented in this work.
6
Tripp, Everett. "Interferometric Optical Readout System for a MEMS Infrared Imaging Detector". Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/222.
Testo completoAbstract (sommario):
MEMS technology has led to the development of new uncooled infrared imaging detectors. One type of these MEMS detectors consist of arrays of bi-metallic photomechanical pixels that tilt as a function of temperature associated with infrared radiation from the scene. The main advantage of these detectors is the optical readout system that measures the tilt of the beams based on the intensity of the reflected light. This removes the need for electronic readout at each of the sensing elements and reduces the fabrication cost and complexity of sensor design, as well as eliminates the electronic noise at the detector. The optical readout accuracy is sensitive to the uniformity of individual pixels on the array. The hypothesis of the present research is that direct measurements of the height change corresponding to tilt through holographic interferometry will reduce the need for high pixel uniformity. Measurements of displacements for a vacuum packaged detector with nominal responsivity of 2.4nm/K are made with a Linnik interferometer employing the four phase step technique. The interferometer can measure real-time, full-field height variations across the array. In double-exposure mode, the current height map is subtracted from a reference image so that the change in deflection is measured. A software algorithm locates each mirror on the array, extracts the measured deflection at the tip of a mirror, and uses that measurement to form a pixel of a thermogram in real-time. A blackbody target projector with temperature controllable to 0.001K is used to test the thermal resolution of the imaging system. The achieved minimum temperature resolution is better than 0.25K. The double exposure technique removes mirror non-uniformity as a source of noise. A lower than nominal measured responsivity of around 1.5nm/K combined with noise from the measurements made with the interferometric optical readout system limit the potential minimum temperature resolution. Improvements need to be made both in the holographic setup and in the MEMS detector to achieve the target temperature resolution of 0.10K.
7
Cools, Antoine. "Beta and neutron imaging with an optical readout Micromegas detector". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP090.
Testo completoAbstract (sommario):
Les détecteurs gazeux ont démontré, au cours de ces dernières décennies, leur haute performance pour l'imagerie de particules radioactives, atteignant des résolutions spatiales inférieures à 100 µm. Les propriétés scintillantes de certains mélanges gazeux, combinées au gain important des détecteurs gazeux et à l'usage d'une caméra à bas bruit électronique, ont permis d'utiliser la lumière scintillée pour l'imagerie. Cette approche permet d'obtenir une large surface de détection et une haute résolution spatiale tout en réalisant l'imagerie en temps réel à un coût par pixel réduit, avec une faible complexité d'analyse des données. Les principaux objectifs de cette thèse sont d'optimiser la résolution spatiale ainsi que la sensibilité du détecteur, soit par une méthode d'acquisition "événement par événement" avec des temps d'acquisition d'image courts, soit par "intégration" avec des temps d'acquisition longs.Un détecteur Micromegas en verre innovant pour la lecture optique a été développé, tirant parti de la haute résolution spatiale inhérente au détecteur Micromegas.L'adaptabilité du gain du détecteur Micromegas liée au mécanisme d'amplification par avalanche, lui permet de couvrir une large gamme de flux et d'énergies de particules. Durant cette thèse, des mesures d'imagerie ont été réalisées à l'aide de sources avec des niveaux de radioactivité inférieurs à un Becquerel et des énergies de quelques keV, jusqu'à des flux caractéristiques d'un synchrotron et d'une source de spallation, avec des énergies dépassant le MeV.Le rendement lumineux du détecteur a été étudié pour différents mélanges gazeux et pour diverses valeurs de gain sous irradiation aux rayons-X afin d'optimiser la sensibilité du détecteur. L'homogénéité et la précision de la réponse du détecteur ont été caractérisées par radiographie à rayons-X. La Fonction d'Étalement du Point (PSF) du Micromegas à lecture optique a été mesurée à l'aide d'un faisceau de rayons-X parallèles de quelques microns d'épaisseur, générés par le rayonnement synchrotron. Cette mesure a permis de déterminer la résolution spatiale du détecteur pour différentes configurations et d'identifier et de quantifier les effets qui rentrent en jeux. L'impact de la microgrille et des piliers sur la réponse en scintillation du détecteur a également été observé et quantifié.Deux applications ont été choisies afin d'illustrer le potentiel du Micromegas à lecture optique: l'autoradiographie pour la quantification d'échantillons tritiés de très faible activitié et la radiographie neutronique à haute résolution en environnement hautement radioactif.L'autoradiographie et le comptage radioactif de rayonnements beta faiblement énergétiques ont été réalisés avec des échantillons de glucose tritié. Des activités inférieures à un Becquerel ont été mesurées avec précision et simultanément sur un grand nombre d'échantillons tout en assurant une reconstruction précise de leur position. Ce travail valide la possibilité de quantifier la concentration de médicaments anticancéreux à l'échelle de cellules tumorales uniques.Enfin, l'utilisation du Micromegas à lecture optique pour la neutronographie a été démontrée en utilisant une source de spallation produisant des neutrons thermiques à un flux d'environ 10⁸ n. s⁻¹cm⁻ ² mA⁻¹. L'uniformité de la réponse du détecteur a été étudiée, et les effets de la diffusion et du parcours moyen des particules dans le gaz sur la netteté de l'image ont été mesurés et comparés à une simulation. Une résolution spatiale de l'ordre de 400 µm a été obtenue en utilisant une amplification à double étages au sein du détecteur MicromegasGaseous detectors have demonstrated, over the past decades, their high performance for imaging radioactive particles, achieving spatial resolutions below 100 µm. The scintillating properties of certain gas mixtures, combined with the significant gain of gaseous detectors and the use of a low-noise camera, have enabled the use of scintillation light for imaging. This approach allows for a large detection surface and high spatial resolution while achieving real-time imaging at a low cost per pixel, with low data analysis complexity. The main objectives of this thesis are to optimize the spatial resolution and sensitivity of the detector, either by an "event-by-event" acquisition method with short image acquisition times or by "integration" with long acquisition times.An innovative glass Micromegas detector for optical readout has been developed, taking advantage of the inherently high spatial resolution of the Micromegas detector. The adaptability of the Micromegas detector's gain, due to the avalanche amplification mechanism, allows it to cover a wide range of particle fluxes and energies. During this thesis, imaging measurements were performed using sources with radioactivity levels below one Becquerel and energies of a few keV, up to fluxes characteristic of a synchrotron and a spallation source, with energies exceeding one MeV.The light yield of the detector was studied for different gas mixtures and various gain values under X-ray irradiation to optimize the detector's sensitivity. The homogeneity and precision of the detector's response were characterized by X-ray radiography. The Point Spread Function (PSF) of the optical readout Micromegas was measured using a parallel X-ray beam a few microns thick, generated by synchrotron radiation. This measurement allowed us to determine the detector's spatial resolution for different configurations and to identify and quantify the effects involved. The impact of the micro-mesh and pillars on the detector's scintillation response was also observed and quantified.Two applications were chosen to illustrate the potential of the optical readout Micromegas: autoradiography, for the quantification of very low-activity tritiated samples and high-resolution neutron radiography in highly radioactive environments.Autoradiography and radioactive counting of low-energy beta radiation were performed with tritiated glucose samples. Activities below one Becquerel were measured accurately and simultaneously on a large number of samples, while ensuring precise reconstruction of their position. This work validates the possibility of quantifying the concentration of anticancer drugs at the scale of single tumor cells.Finally, the use of the optical readout Micromegas for neutron imaging was demonstrated using a spallation source which produces thermal neutrons with a flux of approximately 10⁸ n. s⁻¹cm⁻ ² mA⁻¹. The uniformity of the detector's response was studied, and the effects of the diffusion and the mean free path of particles in the gas on image sharpness were measured and compared to a simulation. A spatial resolution on the order of 400 µm was achieved using double-stage amplification within the Micromegas detector
8
Gunnarsson, Gunnar Hans 1962. "A NEW READOUT TECHNIQUE FOR CD-ROM MULTILEVEL OPTICAL DATA STORAGE". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276464.
Testo completoAbstract (sommario):
A technique is presented that utilizes an on-axis intensity measurement to detect the reflected light from a multiple CD-ROM surface. The thesis includes a computer simulation of the detected signal for scans of various structures and discusses finite size detector effects. A suitably sized detector passes 77% of the total light flux at the detector plane without affecting the depth discrimination property of the technique. Experimentally, a breadboard Height Readout System (HRS) could detect height differences on test relief structures. A signal to noise ratio was obtained that corresponds to a noise equivalent height sensitivity of 30 Angstroms. Therefore, the HRS could discriminate between five levels on the test structure. An addition to the new technique uses a phase plate to determine if the focused beam is going into or out of a pit. Thus, the storage capability per unit area on the disk surface can be increased.
9
Bekker, Scott Henry. "Continuous real-time recovery of optical spectral features distorted by fast-chirped readout". Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/bekker/BekkerS0506.pdf.
Testo completo
10
Toh, Edwin. "Implementation of an optical readout system for high-sensitivity terahertz microelectromechanical sensor array". Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/44019.
Testo completoAbstract (sommario):
Approved for public release; distribution is unlimitedIn this thesis, an optical readout scheme was successfully developed based on the Fourier 4F optical configuration and integrated with a custom-fabricated microelectromechanical system (MEMS)-based, terahertz (THz), detector array. The MEMS THz detector array and 4F Fourier optics were able to transduce the THz scene into an optical signal that was captured by a commercial charged coupled device (CCD) camera for generating images. A quantum cascade laser (QCL) provided the THz illumination for generating images while post-image processing performed background subtraction in order to obtain the THz scene. The Fourier 4F optical readout system that was implemented was able to profile the general shape of the QCL beam pattern and displayed good linearity of response of about 23 gray level values per Kelvin. The concept of optical readout from a micromechanical sensor array was also validated.
11
Schönfeld, Rolf Simon [Verfasser]. "Optical readout of single spins for quantum computing and magnetic sensing / Rolf Simon Schönfeld". Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1029936900/34.
Testo completo
12
Schwarze, Thomas S. [Verfasser]. "Phase extraction for laser interferometry in space : phase readout schemes and optical testing / Thomas S. Schwarze". Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://d-nb.info/1174302674/34.
Testo completo
13
Jeffery, D. R. N. "Test of a GS1 scintillating optical fibre vertex detector with a reticon RA256 photodiode array readout". Thesis, University of Bristol, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381373.
Testo completo
14
McConkey, Nicola. "Detector development for a neutrino detector with combined optical and charge readout in room temperature liquids". Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/69105/.
Testo completoAbstract (sommario):
A room temperature liquid scintillator time projection chamber has the potential to give both ne grained tracking and calorimetry, analogous to liquid argon, only without the cryogenic infrastructure. This type of detector would be invaluable as a cost effective, large volume detector for use in neutrino physics. This motivates the search for candidate liquids with both excellent charge transport properties and optical properties. This work presents results from tests of five dielectric room temperature liquid scintillators; Di isopropyl naphthalene, Phenyl xylyl ethane, Linear alkyl benzene, Mono isopropyl biphenyl, and Mono isopropyl naphthalene, whose charge transport properties are investigated for the first time. The results are also presented from room temperature liquids Tetramethyl pentane, and Cyclopentane, whose optical properties have not previously been investigated. The liquids tested have shown favourable properties, although none of the above liquids has been found to have both charge transport and scintillation light at a suitable level for use in a neutrino detector.
15
Schuldt, Thilo [Verfasser], Achim [Akademischer Betreuer] Peters, Claus [Akademischer Betreuer] Braxmaier e Hans-Jürgen [Akademischer Betreuer] Wünsche. "An optical readout for the LISA gravitational reference sensor / Thilo Schuldt. Gutachter: Achim Peters ; Claus Braxmaier ; Hans-Jürgen Wünsche". Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://d-nb.info/1014974828/34.
Testo completo
16
Dopke, Jens [Verfasser]. "Commissioning of the ATLAS Pixel Detector optical data transmission and studies for readout of the ATLAS IBL and future trackers / Jens Dopke". Wuppertal : Universitätsbibliothek Wuppertal, 2012. http://d-nb.info/1024305066/34.
Testo completo
17
Wensing, Marius [Verfasser]. "Studies on the optical readout of the ATLAS Insertable b-Layer. From firmware development to commissioning of the Back-of-Crate card / Marius Wensing". Wuppertal : Universitätsbibliothek Wuppertal, 2016. http://d-nb.info/1103680722/34.
Testo completo
18
Yang, Rui. "Coupling Two-Dimensional (2D) Nanoelectromechanical Systems (NEMS) with Electronic and Optical Properties of Atomic Layer Molybdenum Disulfide (MoS2)". Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459776436.
Testo completo
19
Troska, Jan Kevin. "Radiation-hard optoelectronic data transfer for the CMS tracker". Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313621.
Testo completo
20
Flick, Tobias. "Studies on the optical readout for the ATLAS Pixel Detector systematical studies on the functions of the back of crate card and the timing of the Pixel Detector /". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982435762.
Testo completo
21
Lisowska, Marta. "Exploring the potential of Micro-Pattern Gaseous Detectors technologies in High Energy Physics applications and beyond". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP094.
Testo completoAbstract (sommario):
Cette thèse de doctorat étudie le potentiel des Détecteurs Gazeux à Micro-Structures (MPGD) pour la Physique des Hautes Énergies et au-delà, en se concentrant sur les avancées en résolution temporelle et en lecture optique. L'objectif principal est le projet PICOSEC Micromegas, visant à développer des détecteurs gazeux à haute précision avec une résolution temporelle cible de O(10) ps pour les Particules au Minimum d’Ionisation. Cette thèse a porté sur l'amélioration des performances et leur extension vers des modules multi-canaux robustes. Les matériaux des photocathodes ont montré que le carbone type diamant (DLC) était prometteur avec une résolution temporelle de 32 ps et une résistance à l'humidité. L'intégration des Micromegas résistifs a amélioré la robustesse contre les décharges, atteignant une résolution temporelle de 12,5 ps avec une photocathode de iodure de césium (CsI). Des prototypes multi-canaux ont été développés pour des surface de détection plus grandes, avec une résolution temporelle inférieure à 18 ps pour un module de 10x10 cm². Cette thèse explore les avantages des techniques de lecture optique pour les MPGDs et cherche à améliorer leurs performances. Elle évalue la résolution spatiale par lecture optique, compare différentes géométries de détecteurs et étudie diverses configurations de GEM pour améliorer la plage dynamique du MIGDAL OTPC. L'optimisation des gaz pour la lecture optique a aussi été abordée, avec des mélanges alternatifs au CF₄ et des décalages de longueur d'ondeThis doctoral dissertation investigates the potential of Micro-Pattern Gaseous Detectors for High Energy Physics and beyond, focusing on time resolution and optical readout advancements. The primary aim was the PICOSEC Micromegas project, concentrating on developing precise-timing gaseous detectors with a target time resolution of O(10) ps for Minimum Ionising Particles. This thesis focused on enhancing performance and scaling it to robust multi-channel detector modules. Research on photocathode materials showed that Diamond-Like Carbon (DLC) was the most promising due to its good time resolution of approximately 32 ps and resistance to humidity. The integration of resistive Micromegas aimed to improve robustness against discharges and ensure stable operation under intense particle beams, achieving a time resolution of approximately 12.5 ps with Cesium Iodide (CsI) photocathode. Finally, multi-channel prototypes were developed to scale to larger detection areas, achieving a time resolution below 18 ps for a 10x10 cm² module. This doctoral dissertation explores the potential benefits of optical readout techniques for MPGDs and aims to enhance their performance. The research included an evaluation of spatial resolution through optical readout, comparing different detector geometries. It investigated various GEM-stack configurations to improve the dynamic range for future modifications of the MIGDAL OTPC, evaluating the maximum achievable gain and light yield across different GEM-based structures. It also recognised the importance of gas optimisation for optical readout by exploring alternative mixtures to CF₄ and wavelength shifters
22
Cervelli, Giovanni. "Analyse, caractérisation et optimisation d'une liaison optique analogique pour l'extraction des données d'un détecteur de particules". Grenoble INPG, 1999. http://www.theses.fr/1999INPG0032.
Testo completoAbstract (sommario):
Deux technologies de liaison optique ont ete considerees pour la lecture de donnees analogiques dans un environnement fortement radioactif : la modulation directe de la source active (une diode laser ingaasp a emission laterale), ou la modulation externe d'un faisceau lumineux par un modulateur a electro-absorption (cavite fabry-perot en inp, utilisee en mode reflectif). Un modele fonctionnel des prototypes de liaison correspondants aux deux solutions alternatives a ete developpe comme support a leur analyse et optimisation. Des procedures de qualification uniformes (et des outils d'evaluation) ont ete developpes pour permettre de determiner les avantages et inconvenients de chaque solution en vue de l'utilisation dans le detecteur cms. Des prototypes correspondants a differentes architectures ou a differentes classes de composants ont ete evalues et compares. Les resultats experimentaux ont constitue un facteur essentiel sur lequel le choix technologique de la collaboration en faveur de la modulation directe s'est base. La liaison optique a une linearite meilleure que 1% et une gamme dynamique instantanee de l'ordre de 1000 : 1 dans une bande passante de 100 mhz. La puissance dissipee et la tolerance aux radiations sont compatibles avec les specifications du detecteur cms, mais impliquent une re-calibration periodique et un fonctionnement proche du seuil du laser. Une gamme dynamique efficace de 800:1 peut etre maintenue tout au long de la vie du detecteur. Une liaison prototype a ete integree dans une chaine de lecture complete, comportant un serialiseur des donnees au niveau du transmetteur et un digitaliseur des donnees au niveau du recepteur (developpes par d'autres groupes). La performance analogique de la chaine a ete optimisee. Sa fonctionnalite a ete demontree grace a l'emulation des signaux du detecteur. Le modele de la liaison optique est exploite pour analyser la dispersion des parametres attendue des 50 000 canaux. La simulation montecarlo est utilisee pour optimiser les specifications des composants, qui seront fixes dans le cour de l'annee 1999.
23
Leclerc, Pierre. "Développement d’un endomicroscope multiphotonique à deux couleurs pour l’imagerie du métabolisme énergétique cellulaire". Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0053/document.
Testo completoAbstract (sommario):
La microscopie multiphotonique est une modalité d’imagerie de pointe offrant des opportunités d’avancées remarquables en biologie mais aussi dans le domaine médical. Afin d’en exploiter pleinement le formidable potentiel au cœur même de la pratique clinique, le développement de nombreuses sondes miniaturisées à fibre optique pour l’endomicroscopie multiphotonique (EMMP) a eu lieu depuis de nombreuses années et dans de nombreux laboratoires français et étrangers. Il s’est pour l'instant confronté à des limitations majeures comme l’impossibilité de recueillir les signaux d’auto-fluorescence des tissus qui sont intrinsèquement faibles comme ceux venant des co-enzymes métaboliques NADH et FAD. Cette limitation compromet l'utilité de l’EMMP en la restreignant à une imagerie morphologique requérant un marquage exogène des tissus. Ce manuscrit présente une architecture d’EMMP permettant de dépasser cette limitation, capable de proposer une imagerie fonctionnelle du métabolisme cellulaire en temps réel, in vivo, in situ, sans marquage. Le prototype d’EMMP proposé est une amélioration du précédent, où les Grisms en réflexions sont remplacés par des Grisms en transmission, permettant d’élargir la bande spectrale d’utilisation et la transmission du système. Ce prototype voit aussi l’adjonction d’un second laser excitateur afin d’accéder aux fluorescences du NADH et du FAD. Les résultats démontrent capable que nous sommes à même d’imager les fluorescences cellulaires intrinsèques au travers de 5 mètres de fibre optique avec une résolution subcellulaire. Parmi celles-ci nous sommes capables d’exciter et de collecter spécifiquement les fluorescences du NADH et du FAD. Enfin nous détectons assez de photons pour disposer d‘informations quantitatives et donc de proposer une image du rapport d’oxydo-réduction optique en endomicroscopieNonlinear microscopy is a cutting edge imaging modality leading to remarkable step forward in biology but also in the clinical field. To use it at its full potential and at the very heart of clinical practice, there has been several development of fiber-based micro-endoscope. The application for those probes is now limited by few major restrictions, such as the impossibility to collect auto-fluorescence signal from tissues theses being inherently weak such as the fluorescence from NADH or FAD. This limitation reduces the usefulness of the micro-endoscope effectively restraining it to morphological imaging modality requiring staining of the tissue. Our aim is to go beyond this limitation, showing cellular metabolism monitoring, in real time, without any staining. The experimental setup is an upgrade of our precedent one where the reflection- based Grism stretcher is replace with a new generation transmission-based Grism stretcher. Another Laser was also added in order to tune the first laser at 860nm to allow FAD imaging and the second one to 760nm for NADH. The results prove that we assess and image the level of NADH and FAD at subcellular resolution through a five-meter-long fiber. Thus we demonstrate that we are capable of measuring the optical redox ratio in a micro-endoscopic configuration
24
Zhang, Bo. "Design, modelling and simulation of a novel micro-electro-mechanical gyroscope with optical readouts". Thesis, Cape Peninsula University of Technology, 2007. http://hdl.handle.net/20.500.11838/1101.
Testo completoAbstract (sommario):
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2007Micro Electro-Machnical Systems (MEMS) applications are fastest development technology present. MEMS processes leverage mainstream IC technologies to achieve on chip sensor interface and signal processing circuitry, multi-vendor accessibility, short design cycles, more on-chip functions and low cost. MEMS fabrications are based on thin-film surface microstructures, bulk micromaching, and LIGA processes. This thesis centered on developing optical micromaching inertial sensors based on MEMS fabrication technology which incorporates bulk Si into microstructures. Micromachined inertial sensors, consisting of the accelerometers and gyroscopes, are one of the most important types of silicon-based sensors. Microaccelerometers alone have the second largest sales volume after pressure sensors, and it is believed that gyroscopes will soon be mass produced at the similar volumes occupied by traditional gyroscopes. A traditional gyroscope is a device for measuring or maintaining orientation, based on the principle of conservation of angular momentum. The essence of the gyroscope machine is a spinning wheel on an axle. The device, once spinning, tends to resist changes to its orientation due to the angular momentum of the wheel. In physics this phenomenon is also known as gyroscopic inertia or rigidity in space. The applications are limited by the huge volume. MEMS Gyroscopes, which are using the MEMS fabrication technology to minimize the size of gyroscope systems, are of great importance in commercial, medical, automotive and military fields. They can be used in cars for ASS systems, for anti-roll devices and for navigation in tall buildings areas where the GPS system might fail. They can also be used for the navigation of robots in tunnels or pipings, for leading capsules containing medicines or diagnostic equipment in the human body, or as 3-D computer mice. The MEMS gyroscope chips are limited by high precision measurement because of the unprecision electrical readout system. The market is in need for highly accurate, high-G-sustainable inertial measuring units (IMU's). The approach optical sensors have been around for a while now and because of the performance, the mall volume, the simplicity has been popular. However the production cost of optical applications is not satisfaction with consumer. Therefore, the MEMS fabrication technology makes the possibility for the low cost and micro optical devices like light sources, the waveguide, the high thin fiber optical, the micro photodetector, and vary demodulation measurement methods. Optic sensors may be defined as a means through which a measurand interacts with light guided in an optical fiber (an intrinsic sensor) or guided to (and returned from) an interaction region (an extrinsic sensor) by an optical fiber to produce an optical signal related to the parameter of interest. During its over 30 years of history, fiber optic sensor technology has been successfully applied by laboratories and industries worldwide in the detection of a large number of mechanical, thermal, electromagnetic, radiation, chemical, motion, flow and turbulence of fluids, and biomedical parameters. The fiber optic sensors provided advantages over conventional electronic sensors, of survivability in harsh environments, immunity to Electro Magnetic Interference (EMI), light weight, small size, compatibility with optical fiber communication systems, high sensitivity for many measurands, and good potential of multiplexing. In general, the transducers used in these fiber optic sensor systems are either an intensity-modulator or a phase-modulator. The optical interferometers, such as Mach-Zehnder, Michelson, Sagnac and Fabry-Perot interferometers, have become widely accepted as a phase modulator in optical sensors for the ultimate sensitivity to a range of weak signals. According to the light source being used, the interferometric sensors can be simply classified as either a coherence interferometric sensor if a the interferometer is interrogated by a coherent light source, such as a laser or a monochromatic light, or a lowcoherence interferometric sensor when a broadband source a light emitting diode (LED) or a superluminescent diode (SLD), is used. This thesis proposed a novel micro electro-mechanical gyroscope system with optical interferometer readout system and fabricated by MEMS technology, which is an original contribution in design and research on micro opto-electro-mechanical gyroscope systems (MOEMS) to provide the better performances than the current MEMS gyroscope. Fiber optical interferometric sensors have been proved more sensitive, precision than other electrical counterparts at the measurement micro distance. The MOMES gyroscope system design is based on the existing successful MEMS vibratory gyroscope and micro fiber optical interferometer distances sensor, which avoid large size, heavy weight and complex fabrication processes comparing with fiber optical gyroscope using Sagnac effect. The research starts from the fiber optical gyroscope based on Sagnac effect and existing MEMS gyroscopes, then moving to the novel design about MOEMS gyroscope system to discuss the operation principles and the structures. In this thesis, the operation principles, mathematics models and performances simulation of the MOEMS gyroscope are introduced, and the suitable MEMS fabrication processes will be discussed and presented. The first prototype model will be sent and fabricated by the manufacture for the further real time performance testing. There are a lot of inventions, further research and optimize around this novel MOEMS gyroscope chip. In future studying, the research will be putted on integration three axis Gyroscopes in one micro structure by optical sensor multiplexing principles, and the new optical devices like more powerful light source, photosensitive materials etc., and new demodulation processes, which can improve the performance and the interface to co-operate with other inertial sensors and navigation system.
25
Yamada, Hirofumi. "Diffusion tensor imaging of the optic chiasm in patients with intra- or parasellar tumor using readout-segmented echo-planar". Kyoto University, 2016. http://hdl.handle.net/2433/216185.
Testo completo
26
高維樑. "Optical Readout Waveforms Simulation in High Density Optical Storage System". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/99214659511033018428.
Testo completoAbstract (sommario):
碩士國立交通大學
光電工程系所
94
As the coming of the tera-era, the demand for the storage capacity is increasing. It is known that the storage capacity is governed by the ratio of wavelength (λ) of the laser diode and the numerical aperture (NA) of the objective lens. Therefore, the optical data storage system is developed toward a shorter wavelength and a higher NA. When the NA of the objective lens is higher than 0.6, the vector nature of light will play an important role during readout process. The optical model combined the advantages of the ray-tracing and vector diffraction is proposed to achieve a faster calculation and still maintain the reliability. Based on the proposed model, the RF signal and servo signals including the focus error signal (FES) and tracking error signals (TES) are demonstrated and successfully verified with the specification under DVD+R/RW system. Moreover, the tolerance analysis of DVD+R/RW system is accomplished. The tilt and defocus effect are simulated and compared with the experimental results to show how the tolerance affect the readout and servo signals. Finally, this thesis discusses a phenomenon which will happen especially in the recordable and re-writable systems called feedthrough. The feedthrough effect is caused by the groove structures on the recordable disc and lead to a variation in focus error signal with the tracking error signal during track seeking process. The feedthrough effect will deteriorated the performance of the focus servo and the origin and the factors that influence feedthrough are discussed.
27
Tai, Chia-ping, e 戴佳萍. "Analyses of the High-NA Optical Pickup Readout". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/55506880589196632636.
Testo completoAbstract (sommario):
碩士國立交通大學
光電工程所
88
In optical recording, the solid immersion lens (SIL) is designed to have the higher numerical aperture (NA) of the optical system, thus to increase the areal recording density. The modeling based on the vector nature is proposed to clarify the behavior of electromagnetic waves in such optics and manifest the inevitability to correct the conventionally used scalar diffraction model. According to the vector model, the spot size in the air gap is about 210 nm for NA=1.6 and 395 nm for NA=0.8. The polarization effect is also examined to identify the difference derived from scalar and vector calculations. The spot size changes to 250 nm on the recording layer for NA=1.6 and 407 nm for NA=0.8. The enlargement of the spot size is more severe for high-NA system, i.e. the depth of focus is reduced, which can limit such near-field optics in practical usage. In signal readout, the higher signal modulation and cut-off frequency is obtained in the high-NA system. This ensures the reading of the data from high-density optical disk. Besides, a useful technique based on using a simple opaque optical filter in the collection path is also introduced to improve the resolution. According to the results of simulation, the higher modulation is still obtained in the high-NA system as the filter is added and also the equalization of the signal is more efficient. When the width of the shading band in the filter becomes larger, more reflected signal is blocked. Though the efficiency of the equalization effect becomes increased, the ratio of the noise from the electronics to the signal intensity is also increased. Thus, the balance between the quality of the readout signal and the ratio of noise should be carefully traded-off.
28
顏文信. "Simulation and research of the optical drive readout system". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/55271902889168851593.
Testo completo
29
Lin, Tzu-Yang, e 林子揚. "A Novel 3D Optical Proximity Sensor and Its Readout Circuit". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/38987585577094027377.
Testo completoAbstract (sommario):
碩士國立交通大學
電機與控制工程系所
97
The thesis proposes a novel 3D optical proximity sensor. It is a non-contact positioning sensor, which can sense the approaching distance of objects without touching. This device is composed of light-emitting diodes and home-made polymer photo-detectors. The light-emitting diode produces a light signal, and then the light signal is received by the polymer photo-detector via reflections of the measured object. Organic polymer materials attract a lot of interests since they can reduce the cost of manufacture, can become flexible, and can make the large area on flexible substrate. As a result of these characteristics, the optical proximity sensor could be applied on the development of the non-touching panel or flexible keyboard in the future. The problem of the optical proximity sensor is that the wide spectrum response range of the polymer photo-detector causes the polymer photo-detector to receive the background current before the light-emitting diode is turned on, which results in the polymer photo-detector being unable to locate the peak emission of the light-emitting diode when the light-emitting diode is turned on. Therefore, the polymer photo-detector detected the photocurrent, which included the background current and the current which is received by reflections of the measured object. The design of the circuit is the operation principle through active pixel circuit, sampling circuit, amplifier circuit and the decision of proposed chip parameters is determined by circuit simulation. The circuit is regarded low power and low cost as the design principle. Furthermore, the time sequence control is generated by FPGA to accomplish the operation of the whole circuit. The aim is to remove background current, and to detect the corresponding output voltage of photocurrent that is received by the polymer photo-detector via reflections of the measured object. Finally, the human machine interface is constructed by LABVIEW to create 3D vision tracing of sensed object. The proposed chip, with a die area of 0.55×0.85 mm2 is patronized by National Applied Research Laboratories National Chip Implementation Center (NARL NCIC), accomplished by using Taiwan Semiconductor Manufacturing Company (TSMC) 0.35μm 2P4M 3.3V mixed‐signal CMOS process.
30
La, Rana Adele. "An optical readout for the gravitational reference sensor of LISA". Tesi di dottorato, 2008. http://www.fedoa.unina.it/1793/1/La_Rana_Fisica_Fondamentale_ed_Applicata.pdf.
Testo completo
31
Hsu, Wei-Hsuan, e 許偉軒. "A New Active 3D Optical Proximity Sensor Array and Its Readout Circuit". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/83019786060882572682.
Testo completoAbstract (sommario):
碩士國立交通大學
電控工程研究所
98
The study proposes a new active pixel sensor (APS) circuit and the associated 3D optical proximity sensing circuit to eliminate the effects of background lighting. The 3D optical proximity sensing system is a non-contact positioning sensor, which senses the approaching distances of objects without touching. The system is capable of 2D sensing and third-axis sensing, the 3D proximity sensing. This system is composed of light-emitting diodes and photo-detectors. The light emitting diode produces a light signal. The light signal is received by the photo detector via reflections of the measured object. The system determines the height of the object with the light intensity measured by the photo detector. In order to adapt to different environments, the study proposes a special circuit that eliminates the background light. After eliminating background light circuit, the results of the algorithm computation is illustrated by a LABVIEW program. A new active pixel sensor is also proposed in the study. The active pixel sensor is used to convert the light to the voltage, and it can improve the resolution and reduce the noise. The standard and official active pixel sensor is a 3T-structure APS (or 3T-APS). The drawback of 3T-APS is that the output range is limited by the original circuit design. The maximum output cannot be up to bias voltage. The new APS resolution is better than the standard 3T-APS resolution in this aspect. It is a good improvement in terms of not only the CMOS sensor but also the 3D optical proximity sensing circuit. The circuits are accomplished by Taiwan Semiconductor Manufacturing Company (TSMC) 0.35μm 2P4M 3.3V mixed‐signal CMOS process. The system is composed of the LED/PD array, designed IC and the LABVIEW program. The proposed chips, with the die area of 1.289×1.289 mm2 and 0.8× 1.220 mm2 are fabricated by National Applied Study Laboratories National Chip Implementation Center (NARL NCIC).
32
Campbell, Warren Gerard. "Readout of polymer gel dosimeters using a prototype fan-beam optical computed tomography scanner". Thesis, 2015. http://hdl.handle.net/1828/5982.
Testo completoAbstract (sommario):
New radiation therapy (RT) techniques for treating cancer are continually under development. Our ability to demonstrate the safe and accurate implementation of new RT treatment techniques is dependent on the information provided by current dosimetric tools. Advanced dosimetric tools will become increasingly necessary as treatments become more complex. This work examines the readout of an advanced dosimeter --- the polyacrylamide, gelatin, and tetrakis (hydroxymethyl) phosphonium chloride (PAGAT) dosimeter --- using a prototype fan-beam optical computed tomography (CT) scanner.
A number of developments sought to improve the performance of the optical CT device. A new fan-creation method (laser diode module) and new matching tank were introduced. Artefact removal techniques were developed to remove flask seam artefacts and ring artefacts via sinogram space. A flask registration technique was established to achieve reproducible placement of flasks in the optical CT scanner. A timing-correction technique was implemented to allow for the scanning of continuously rotating samples.
A number of experiments examined factors related to the PAGAT dosimeter. Comparisons of post-irradiation scans to pre-irradiation scans improved dosimeter readout quality. Changes to the PAGAT dosimeter cooling/scanning routine provided further improvements to dosimeter readout. Evaluations of calibration curves showed that a linear calibration curve was less capable of describing PAGAT dose response than a quadratic calibration curve. Intra-gel calibration using another dose distribution was shown to be no less accurate than self calibration, but inter-gel calibrations saw a statistically significant increase in absolute readout errors.
A set of investigations examined how optical CT scanning protocols affected readout quality for PAGAT dosimeters. Doubling the dose delivered to the dosimeter doubled the signal-to-noise ratio. Acquiring and averaging additional light profiles at each projection angle provided only slight reductions in readout noise. Sampling a higher number of projection angles provided substantial reductions in readout noise. Those reductions in readout noise were not lost when sinograms with many projections were encapsulated into sinograms of fewer projection angles. Detector element binning (sinogram space) and pixel binning (image space) also provided substantial reductions in readout noise. None of these elements of the scanning protocol had statistically significant effects on readout errors.
Finally, distinct imaging artefacts seen throughout this work were shown to be caused by radiation-induced refractive index changes in PAGAT dosimeters. Radiation-induced refraction (RIR) artefacts result when dose gradients caused the refraction of fan-beam raylines towards high dose regions. A filtering technique was developed to remove RIR artefacts in sinogram space, but this technique caused substantial blurring to the measured dose distribution.Graduate
0760
0756
0752
warreng1983@gmail.com
33
黃仕臣. "Analysis of disk tilt effect on readout data signal and compensation in an optical driver". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/79322568536228296030.
Testo completoAbstract (sommario):
碩士國立清華大學
動力機械工程學系
92
High-speed rotation of the disk in optical driver always causes disk tilt, and then produces aberration. Aberration due to disk tilt would affect the intensity of the laser beam on the disk, and reduce the quality of the readout signal. From the specification of the DVD, the effect of small disk tilt still could be endured. However, as the storage density increases, this effect should be taken into consideration in order to improve the signal quality. This thesis will concentrate on the influences due to disk tilt on the high-frequency readout signal in DVD optical driver. Several optical theories used to analyze such deviations and to establish the mathematical model of the optical pickup will be studied. Then the model of the overall optical driver system in reading the data from the disk would be constructed. The variation of HF signal with period from 3T to 11T and 14T is simulated and examined under different disk tilt angles. Finally, the HF signal affected by disk tilt will be compensated by modifying the power of the laser diode. All simulations within this thesis are based on the mathematical model and the MATLAB software.
34
Wu, Yi-Cheng, e 吳翊丞. "Design and Implementation of the OLED Driving and OPD Readout Circuitry for Optical Vibration Sensor". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/umv8w6.
Testo completoAbstract (sommario):
碩士國立交通大學
電控工程研究所
106
This thesis presents an organic light-emitting diode (OLED) drive circuit and an organic photo detector (OPD) readout circuits for a vibration sensor. Vibration sensor is consist of micro-electro-mechanical systems (MEMS), OLED and OPD which needs to be compact for many applications in automation or consumer electronics, and microelectromechanical structures are a convenient way to implement such sensors. The light flux is typically generated by an OLED located on top of the structure and the modulated light flux is measured by an OPD. The OLED drive circuit contains pulse width modulation (PWM) driver to control PWM output for optimization of voltage operation is designed in order to minimize power consumption efficiency of device. The readout circuit includes a trans-impedance amplifier (TIA) to convert incident light of OPD to voltage output, a 14-bit analog-to-digital converter (ADC) to extract amplitude of vibration level, circuit to generate clock for time-to-digital converter (TDC) which detect frequency of vibration sensor. The designed circuit has been successfully fabricated by using TSMC 0.18-μm CMOS process, where the active area is 1.012 mm2. The power consumption of chip is about 6.2 mW. The measured frequency of PWM signal is about 200 kHz and duty cycle is 50%. The frequency range of the vibration which could be sensed well is about 10 Hz~1.5 kHz.
35
Jen, Tsung-Huei, e 任宗輝. "Readout Scheme by Pulsed Irradiation Center Aperture Detection on Magnetically Induced Super Resolution Magnetio-Optical Disks". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/69351577344456505847.
Testo completoAbstract (sommario):
碩士國立交通大學
光電工程研究所
85
Magnetically induced super resolution (MSR) is used to read below-diffraction-limited marks recorded on magneto-optical (MO) disks. In an MSR disk, readout signal characteristies is mainly determined by its temperature profile. So, in order to accurately control the temperature profile, a readout by pulsed irradiation is applied. Nanosecond pulse driven by channel clock is irradiated onto MO media to create a quasi-circular temperature profile on an optical disk spinning at high speed. Exchange coupling between recording and readout layers of an MSR-CAD disk can yield a quasi-circular sub-um aperture to effectively derive a readout signal from sub-um marks recorded on the disks. In this study, MSR-CAD is proved very suitable for "pulsed readout" because the readout CNR is 1.9dB larger than that with conventional DC method and the readout characteristics is thus clearly improved.
36
Nguyen, Thuy Thi Ha. "Förster resonance energy transfer (FRET) as an optical readout for transcription factor-DNA binding in biosensing applications". Thesis, 2019. https://hdl.handle.net/2144/36021.
Testo completoAbstract (sommario):
An alternative molecular recognition approach was developed for sensing small molecule analytes using the differential binding of an allosteric transcription factor (TF, specifically TetR) to its cognate DNA as the molecular recognition element coupled with Förster resonance energy transfer (FRET) to yield an internally calibrated optical signal transduction mechanism. Sensors were evaluated comprising Cy5-modified DNA (FRET acceptor) with either a tdTomato-TetR fusion protein (FP-TF) or quantum dot-TetR conjugate (QD-TF) as the FRET donor by measuring the ratio of acceptor and donor fluorescence intensities (FA/FD) with titrations of a derivative of the antibiotic tetracycline, anhydrous tetracycline (aTc). A proof-of-concept FRET-based biosensor was successfully demonstrated through the modulation of FA/FD signal intensities based on varying analyte concentrations. Sensor design parameters affecting overall signal-to-noise ratio and sensitivity of the sensors are also identified.2020-06-03T00:00:00Z
37
Flick, Tobias [Verfasser]. "Studies on the optical readout for the ATLAS Pixel Detector : systematical studies on the functions of the back of crate card and the timing of the Pixel Detector / vorgelegt von Tobias Flick". 2006. http://d-nb.info/982435762/34.
Testo completo
38
Breer, Stefan. "Wellenlängenmultiplexing mit thermisch fixierten Volumenphasenhologrammen in photorefraktiven Lithiumniobat-Kristallen". Doctoral thesis, 2000. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2000090850.
Testo completoAbstract (sommario):
Wavelength division multiplexing (WDM) is essential for further enhancement of the transmission capacities of optical
telecommunication systems. Key devices in WDM networks are multiplexing/demultiplexing components, which enable
the combination/separation of several carrier waves with different wavelengths for the purpose of simultaneous
transmission through one optical fibre. These components can be realized using Bragg diffraction from volume
holographic gratings. Especially reflection holograms provide a pronounced wavelength selectivity which makes them
attractive for free-space WDM applications.
Holograms can be stored permanently in photorefractive lithium niobate crystals by the method of Thermal Fixing.
Heating of the crystal during or after the recording process and subsequent development by homogeneous illumination at
room temperature create nonvolatile holograms. The recording and development processes of Thermal Fixing in iron-
and copper-doped lithium niobate crystals were investigated. Macroscopic Gaussian-shaped intensity patterns were
used to analyse the origin of the fixing mechanism. Spatially resolved absorption measurements were performed to
determine the concentration profiles of electron traps (Fe II/III) and protons. Results of computer simulations were
compared with experimental results, which showed that protons can be found to work as compensators during hologram
recording at temperatures around 180 degree C. Nevertheless thermal fixing without protons was possible, another
compensation mechanism stood in. The obtained refractive-index changes were due to the electro-optic effect, other
contributions could be neglected.
With this detailed knowledge about thermal fixing, a two-channel demultiplexing unit was built by superposition of two
thermally fixed reflection holograms in an iron-doped lithium niobate crystal. For this purpose a special two-beam
interference setup with precisely adjustable writing angles was arranged in a vacuum chamber to eliminate thermally
induced phase disturbances of the holographic recording procedure. Continuous development of the holograms by
incoherent light was necessary. In the dark, the enhanced dark conductivity of the crystal used gave rise to a hologram
degradation within about one day. Large diffraction efficiencies were attained (intensity losses between 2.3 and 5.2 dB
only) uilizing crystals with high-quality polished surfaces. The crosstalk supression of the realized demultiplexer was >
25 dB, which is comparable with the performance of other multiplexing techniques like fibre Bragg gratings or
arrayed-waveguide gratings. The low polarization dependence of the demultiplexer can be improved by superposition of
two holograms for each channel.
39
Rink, Alexandra. "Point-based Ionizing Radiation Dosimetry Using Radiochromic Materials and a Fibreoptic Readout System". Thesis, 2008. http://hdl.handle.net/1807/11254.
Testo completoAbstract (sommario):
Real-time feedback of absorbed dose at a point within a patient can help with radiological quality assurance and innovation. Two radiochromic materials from GafChromic MD-55 and EBT films have been investigated for applicability in real-time in vivo dosimetry of ionizing radiation. Both films were able to produce a real-time measurement of optical density from a small volume, allowing positioning onto a tip of an optical fibre in the future. The increase in optical density was linear with absorbed dose for MD-55, and non-linear for EBT. The non-linearity of EBT is associated with its increased sensitivity to ionizing radiation compared to MD-55, thus reaching optical saturation at a much lower dose. The radiochromic material in EBT film was also shown to polymerize and stabilize faster, decreasing dose rate dependence in real-time measurements in comparison to MD-55. The response of the two media was tested over 75 kVp – 18 MV range of x-ray beams. The optical density measured for EBT was constant within 3% throughout the entire range, while MD-55 exhibited a nearly 40% decrease at low energies. Both materials were also shown to be temperature sensitive, with the change in optical density generally decreasing when the temperature increased from ~22°C to ~37°C. This was accompanied by a shift in the peak absorbance wavelength. It was illustrated that some of this decrease can be corrected for by tracking the peak position and then multiplying the optical density by a correction factor based on the predicted temperature. Overall, the radiochromic material in GafChromic EBT film was found to be a better candidate for in vivo real-time dosimetry than the material in GafChromic MD-55.
A novel mathematical model was proposed linking absorbance to physical parameters and processes of the radiochromic materials. The absorbance at every wavelength in the spectrum was represented as a sum of absorbances from multiple absorbers, where absorbance is characterized by its absorption coefficient, initiation constant, and polymerization constant. Preliminary fits of this model to experimental data assuming two absorbers suggested that there is a trade-off between EBT’s greater sensitivity and its dose linearity characteristics. This was confirmed by experimental results.
40
Filippov, Oleg. "Vectorial beam coupling in fast photorefractive crystals with AC-enhanced response". Doctoral thesis, 2004. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2004092812.
Testo completoAbstract (sommario):
We develop a theory of vectorial wave coupling in cubic photorefractive crystals placed in an alternating ac-field to enhance the nonlinear response. First we analytically and numerically investigate the dependences of the first Fourier harmonics of the space-charge field, induced in an AC-biased sillenite crystal by a light-interference pattern, on the light contrast m. The data obtained was used to extend the vectorial beam-coupling theory on the whole contrast region. In particular, we proved in the general case that despite of essential differences between thediffusion and AC nonlocal responses the later keeps the light interference fringes straight during the interaction. This fundamental feature allows, under certain restrictions, to reduce the nonlinear problem of vectorial coupling to the known linear problem of vectorial Bragg diffraction from a spatially uniform grating, which admits an exact solution. As a result, the nonlinear vectorial problem can be effectively solved for a number of practically important cases.The developed theory was applied to describe the transformation of a momentary phase changes of one of the input beams into the output intensity modulation (so-called grating translation technique). In contrast to the previous studies, we take into account the change of the space-charge field amplitude across the crystal (the coupling effects). The theory developed is employed to optimize the conditions for the linear signal detection under polarization filtering for the transverse and longitudinal optical configurations. We also analyze the possibility of the linear detection without polarization filtering.Illumination of AC-biased photorefractive BTO crystals with a coherent light beam results in development of strong nonlinear scattering. We investigate the angular and polarization characteristics of the scattered light for the diagonal optical configuration and different polarization states of the pump.
41
(10702782), Ashwin Nagarajan. "Novel Analysis Framework Using Quantum Optomechanical Readouts For Direct Detection Of Dark Matter". Thesis, 2021.
Cerca il testo completoAbstract (sommario):
With the increase in
speculation about the nature of our universe, there has been a growing need to
find the truth about Dark Matter. Recent research shows that the Planck-Mass
range could be a well-motivated space to probe for the detection of Dark Matter
through gravitational coupling. This thesis dives into the possibility of doing
the same in two parts. The first part lays out the analysis framework that
would sense such an interaction, while the second part outlines a prototype
experiment that when scaled up using quantum optomechanical sensors would serve
as the skeleton to perform the analysis with.
42
Gardner, James Walter. "Improving future gravitational-wave detectors using nondegenerate internal squeezing". Thesis, 2021. http://hdl.handle.net/1885/256029.
Testo completoAbstract (sommario):
Gravitational waves are "ripples" in spacetime emitted by massive
astrophysical events. Over the past decade, interferometric
detectors have been used to measure gravitational waves from the
binary mergers of black holes and neutron stars to learn more
about such systems; these gravitational waves had frequencies
around 100 Hz. Other frequencies of gravitational waves are
thought to exist and contain valuable information but are yet to
be detected. For example, detecting kilohertz (1–4 kHz)
gravitational waves from binary neutron-star mergers could be
used to further constrain the neutron-star equation-of-state and
better understand exotic states of matter. However, to do so, the
sensitivity of current detectors will need to be extended from
100 Hz to the kilohertz regime.
The kilohertz sensitivity of current gravitational-wave detectors
is limited by quantum noise from the fundamental quantum
uncertainties in the state of light inside the detector. This
noise can be mitigated by replacing the vacuum fluctuations
entering the readout port of the detector with squeezed states.
In this thesis, I investigate a new technique to improve
kilohertz sensitivity by placing a nondegenerate squeezer inside
the detector. This technique, called nondegenerate internal
squeezing, improves sensitivity by amplifying the detector's
response to the gravitational-wave signal more than it increases
the quantum noise. To assess its feasibility, I derive an
analytic Hamiltonian model of nondegenerate internal squeezing
and calculate its sensitivity and stability as well as analyse
its tolerance to the realistic optical losses expected in a
future gravitational-wave detector. My model indicates that
nondegenerate internal squeezing is stable, robust to detection
loss in the readout, and provides a viable alternative to other
proposals to improve kilohertz sensitivity. I demonstrate a
technique to determine its squeezing threshold and, therefore,
the limits of its operation. I find that nondegenerate internal
squeezing could feasibly improve the sensitivity of a future
detector to 1–4 kHz gravitational waves. I also explore an
alternative readout scheme that is promising for broadband
0.1–4 kHz sensitivity.