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Casanueva, Diaz Julia. « Control of the gravitational wave interferometric detector Advanced Virgo ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS209/document.
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La première détection d'une Onde Gravitationnelle (OG) a été faite le 14 Septembre 2015 par la collaboration LIGO-Virgo avec les deux détecteurs de LIGO. Elle a été émise par la fusion de deux Trous Noirs, fournissant ainsi la première preuve directe de l’existence des Trous Noirs. Advanced Virgo est la version améliorée de l’interféromètre Virgo et il va rejoindre les détecteurs LIGO dans les mois qui suivent. Le passage d'une OG induit un changement différentiel de la distance entre masses-test (uniquement sensibles à la force gravitationnelle). Cette variation de distance est proportionnelle à l'amplitude de l'OG, néanmoins le déplacement le plus grand qui peut être observé depuis la Terre est de l'ordre de 10⁻¹⁹ m/sqrt(Hz) en terme de densité spectrale. C'est pour cela que l’interféromètre de Michelson est l'instrument idéal pour détecter cet effet différentiel. Les détecteurs d’OG utilisent des miroirs suspendus, qui se comportent comme masses-test. Le passage d'une OG va produire un changement dans la distance entre les miroirs qui va modifier la condition d’interférence et donc une variation de puissance lumineuse mesurée par la photodiode de détection. Cependant, un Michelson simple n'est pas assez sensible et des améliorations ont été ajoutées. La première génération de détecteurs a ajouté des cavités Fabry-Pérot dans les bras pour augmenter le chemin optique. De plus un nouveau miroir a été ajouté pour recirculer la lumière réfléchie vers le laser et augmenter la puissance effective, en créant une nouvelle cavité connue comme Power Recycling Cavity (PRC). Son effet est d’autant plus important que le Michelson est en fait optimalement réglé sur une frange noire. Tous les miroirs du détecteur ressentent le bruit sismique et les longueurs des cavités, entre autres, changent en permanence. Il est donc nécessaire de contrôler activement la position longitudinale et angulaire des cavités pour les maintenir en résonance. Pendant ma thèse j'ai étudié le contrôle de Advanced Virgo d’abord en simulation puis pendant le commissioning lui-même. D'abord j'ai simulé la stratégie de contrôle utilisée dans Virgo avec des simulations modales. L'objectif était de vérifier si la même stratégie pouvait être appliquée à Advanced Virgo ou s'il fallait l'adapter. Avec Advanced Virgo les cavités Fabry-Pérot ont une finesse plus grande ce qui entraîne de nouveaux effets dynamiques et qui demande une stratégie de contrôle spéciale, stratégie que j'ai modifiée pour l'adapter aux besoins du commissioning. Concernant la PRC, j’ai étudié l'impact de sa stabilité dans le fonctionnement de l’interféromètre. Comme elle est très proche de la région d’instabilité, l’onde lumineuse être très sensible à l'alignement et a l'adaptation du faisceau à la cavité. J’ai vérifié avec les simulations son impact sur les contrôles longitudinaux, qui peuvent devenir instables, et une solution a été validée. Ensuite j'ai utilisé cette information pour le commissioning d'Advanced Virgo. Dans cette thèse les détails du commissioning des contrôles longitudinal et angulaire de l’interféromètre sont présentés. La stabilisation en fréquence est aussi présentée, puisqu'elle joue un rôle très important dans le contrôle de l’interféromètre car étant le bruit dominantThe first detection of a Gravitational Wave (GW) was done on September 14 th of 2015 by the LIGO-Virgo collaboration with the two LIGO detectors. It was emitted by the merger of a Binary Black Hole, providing the first direct proof of the existence of Black Holes. Advanced Virgo is the upgraded version of the Virgo interferometer and it will join the LIGO detectors in the next months. The passage of a GW on Earth induces a change on the distance between test masses (experiencing only the gravitational interaction) in a differential way. This distance variation is proportional to the amplitude of the GW however the largest displacement observable on Earth will be of the order of 10⁻¹⁹ m/sqrt(Hz). Taking this in account, a Michelson interferometer is the ideal instrument to detect this differential effect. GWs detectors will use suspended mirrors to behave as test masses. The passage of a GW will cause a change on the distance between the mirrors that will spoil the interference condition, allowing some light to leak to the detection photodiode. However, a simple Michelson interferometer does not provide enough sensitivity. For this reason the first generation of detectors added Fabry-Perot cavities in the arms, in order to increase the optical path. A second change was the addition of an extra mirror in order to recycle the light that comes back towards the laser, to increase the effective power, creating a new cavity also known as Power Recycling Cavity (PRC). Its effect is more important when the Michelson is tuned in an optimal way in a dark fringe. All the mirrors of the detector are affected by the seismic noise and so their distance is continuously changing. It is necessary to control the longitudinal and angular position of the cavities in order to keep them at resonance. During my thesis I have studied the control of Advanced Virgo using simulation and during the commissioning itself. First of all I have simulated the control strategy used in Virgo using modal simulations. The aim was to check if the same strategy could be applied to Advanced Virgo or if it needs adaptation. In Advanced Virgo the Fabry-Perot cavities have a higher finesse, which arises new dynamical problems and requires a special control strategy that I have modified to match the commissioning needs. Regarding the PRC, we have studied the impact of its stability on the performance of the interferometer. As it is very close from the instability region, the electrical field inside will be very sensitive to alignment and matching of the laser beam. We have checked using simulations its impact on the longitudinal controls, which can become unstable, and a solution has been validated. Then I have used this information during the commissioning of the Advanced Virgo detector. In this thesis the details of the commissioning of the longitudinal and angular control of the interferometer will be presented. It includes the frequency stabilization, which has a key role in the control of the interferometer, since it is the dominant noise
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Nishizawa, Atsushi, Seiji Kawamura, Tomotada Akutsu, Koji Arai, Kazuhiro Yamamoto, Daisuke Tatsumi, Erina Nishida et al. « Laser-interferometric detectors for gravitational wave backgrounds at 100 MHz : Detector design and sensitivity ». American Physical Society, 2008. http://hdl.handle.net/2237/11308.
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Tripp, Everett. « Interferometric Optical Readout System for a MEMS Infrared Imaging Detector ». Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/222.
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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.
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Regehr, Martin W. Drever Ronald W. P. Drever Ronald W. P. Yariv Amnon Raab Frederick J. « Signal extraction and control for an interferometric gravitational wave detector / ». Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-10192007-092215.
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Gossler, Stefan. « The suspension systems of the interferometric gravitational-wave detector GEO 600 ». [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972116710.
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Kerr, G. A. « Experimental developments towards a long-baseline laser interferometric gravitational radiation detector ». Thesis, University of Glasgow, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378181.
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Tröbs, Michael. « Laser development and stabilization for the spaceborne interferometric gravitational wave detector LISA ». [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974983705.
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Hughes, Roy John. « The application of array detector technology to interferometric spectroscopy : design, analysis and development ». Thesis, Queensland University of Technology, 1994.
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Gras, Slawomir M. « Opto-acoustic interactions in high power interferometric gravitational wave detectors ». University of Western Australia. School of Physics, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0093.
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[Truncated abstract] Advanced laser interferometer gravitational wave detectors require an extremely high optical power in order to improve the coupling between the gravitational wave signal and the optical field. This high power requirement leads to new physical phenomena arising from nonlinear interactions associated with radiation pressure. In particular, detectors with multi-kilometer-long arm cavities containing high density optical fields suffer the possibility of 3-mode opto-acoustic interactions. This involves the process where ultrasonic vibrations of the test mass cause the steady state optical modes to scatter. These 3-mode interactions induce transverse optical modes in the arm cavities, which then can provide positive feedback to the acoustic vibrations in the test masses. This may result in the exponential growth of many acoustic mode amplitudes, known as Parametric Instability (PI). This thesis describes research on 3-mode opto-acoustic interactions in advanced interferometric gravitational wave detectors through numerical investigations of these interactions for various interferometer configurations. Detailed analysis reveals the properties of opto-acoustic interactions, and their dependence on the interferometer configuration. This thesis is designed to provide a pathway towards a tool for the analysis of the parametric instabilities in the next generation interferometers. Possible techniques which could be helpful in the design of control schemes to mitigate this undesirable phenomenon are also discussed. The first predictions of parametric instability considered only single interactions involving one transverse mode and one acoustic mode in a simple optical cavity. ... In Chapter 6, I was able to make use of a new analytical model due to Strigin et al., which describes parametric instability in dual recycling interferometers. To make the solution tractable, it was necessary to consider two extreme cases. In the worst case, recycling cavities are assumed to be resonant for all transverse modes, whereas in the best cases, both recycling cavities are anti-resonant for the transverse modes. Results show that, for the worst case, parametric gain values as high as ~1000 can be expected, while in the best case the gain can be as low as ~ 3. The gain is shown to be very sensitive to the precise conditions of the interferometer, emphasising the importance of understanding the behaviour of the detectors when the cavity locking deviates from ideal conditions. Chapter 7 of this thesis contains work on the observation of 3-mode interactions in an optical cavity at Gingin, which confirms the analysis presented here, and also a paper which shows how the problem of 3-mode interactions can be harnessed to create new devices called opto-acoustic parametric amplifiers. In the conclusions in Chapter 8, I discuss the next important steps in understanding parametric interactions in real interferometers including the need for more automated codes relevant to the design requirements for recycling cavities. In particular, it is pointed out how the modal structure of power and signal recycling cavities must be understood in detail, including the Gouy phase for each transverse mode, to be able to obtain precise predictions of parametric gain. This thesis is organised as a series of papers which are published or have been submitted for publication. Such writing style fills the condition for Ph.D. thesis at the University of Western Australia.
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BADARACCO, FRANCESCA. « Newtonian Noise studies in 2nd and 3rd generation gravitational-wave interferometric detectors ». Doctoral thesis, Gran Sasso Science Institute, 2021. http://hdl.handle.net/20.500.12571/16065.
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This thesis work fits in the Newtonian noise (NN) cancellation framework for gravitational-wave (GW) detectors of 2nd and 3rd generation.
At frequencies below 20 Hz the NN affects GW detectors by generating gravity gradients that mask the GW signals that we want to measure.
My work can be divided in three main tasks: the optimization of a seismic array for the NN cancellation in underground detectors, the optimization of a seismic array for Advanced Virgo + (which, respect to the former one, relied on seismic measurements and not on a seismic model) and the evaluation of the NN and the seismic field at the KAGRA site. I will briefly summarize in the following the main results of these three works.
In the first work I performed a global optimization for finding the optimal locations of an array of sensors for the NN cancellation for underground detectors. Since we need to search for the optimal positions of N sensors in a 3D space, the computational efforts required are very demanding.
At the present time, seismic correlations in the relevant frequency band for ET from 3Hz to 20Hz are not available. So we modelled the seismic field as isotropic and homogeneous. With this work I was able to assess the feasibility of applying active NN reduction in underground detectors and reaching a factor 10 of noise reduction with 15 sensors at 10 Hz. In 2019 this work was published.
The second work I made during my PhD was conceptually similar to the previous one but very different in the approach used to solve it. Exploiting a theoretical model in Virgo was not an option given its complicated structure. I then used Virgo's seismic data to run the optimization of sensor locations. The main challenge here was that I had to perform a gaussian process regression over a 4D space, and not enough data were available for this purpose. I found a way to bypass the regression over the 4D space by exploiting the convolution theorem. This allowed me to perform the regression over a space with reduced dimension, i.e., in 2D.
The global optimization algorithm was then run hundreds of times in order to statistically prove the global minimum, exactly as done in the work for the underground optimization. The results proved that with 15 seismometers we can reach a noise reduction factor of 3-7, which is enough for the aimed sensitivity of the next observing runs. The results of this work were then used to set the array that will be used to cancel the NN in Advanced Virgo +. This work has been published in 2020. This approach could also be useful in future, where it will be needed to optimize underground seismic arrays with real seismic data.
Finally, in the third work I used seismic data collected in the Kamioka mine (where the gravitational-wave detector KAGRA is hosted) to investigate the seismic noise caused by the infrastructure and to calculate a NN budget. These are important aspects that need to be investigated in view of the 3rd generation GW detector Einstein Telescope.
The data indicated that the infrastructure noise starts to be important well above 10 Hz, where the NN loses its impact on the detector and where the seismic isolation system is capable of killing the noise. Moreover, I used the data from three seismometers to perform a beamforming analysis and find the seismic velocities and the seismic wave main directions. The extracted values were then used as a reference for the estimation of the NN budget. For completeness, I also estimated the NN budget coming from surface Rayleigh waves. This was made by exploiting the data of the F-net network, in Japan. I then showed that the NN from surface and body waves can be neglected for KAGRA.
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Ashraf, Shakeel. « Evolution of IR Absorber for Integration in an IR Sensitive CO2 Detector ». Thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-14088.
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The maximum sensitivity of a thermal IR sensor can be available either by means of the sensor material, having its own absorbing properties, or by the deposition of an additional absorber structure on the detector surface. In this thesis, the theory of two absorption structures is discussed. The first is called the interferometric absorber structure. The second structure under investigation uses a lead selenide layer for the IR absorption. In the interferometric structure, a new epoxy material SU8-2002 was used as a dielectric medium. This material has a very low thermal conductivity of 0.3 W/mK, which makes it suitable for thermal detectors. The interferometric structure is based on three layers, a 40–60 Å thick Ti layer, a SU8–2002 layer with a thickness of 2000 Å thick and a 2000Å Al layer. Using standard cleanroom processing an interferometric structure was fabricated. Transfer matrix theory was used in order to simulate the interferometric structure and the lead selenide was fabricated by means of an argon-plasma sputtering process. Both fabricated samples were characterized through Fourier transfer infrared (FTIR) spectroscopy together with a specular reflectance accessory. The thicknesses of the added layers were measured using Atomic force microscopy (AFM) for both the interferometric and lead selenide structure. It was determined that by changing the reflective index value of the SU8-2002 from the reported value of 1.575 to about 2.40 that this provided a better agreement with the experimental results. The absorption results for the interferometric structure were determined to be approximately 82–98% for the wavelength region of 2-20µm at 30 degree. The PbSe absorption spectra showed 30%–50% absorption for the wavelength region 2.5 – 6.67μm.
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Rogan, Aaron Matthew. « Gravitational wave detection, detector characterization, and parameter estimation using a network of interferometer detectors ». Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/Fall2006/a_rogan_121406.pdf.
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Boulanger, Jean-Luc. « Detection interferometrique des ondes de gravitation : dynamique des fabry-perot pendulaires, evaluation des reseaux d'antennes ». Paris 6, 1988. http://www.theses.fr/1988PA066099.
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Ce travail comporte deux parties qui s'inscrivent dans le cadre general de la detection interferometrique des ondes de gravitation. Certains detecteurs utilisent des cavites fabry-perot pendulaires dont nous etudions la dynamique dans la 1ere partie. Nous discutons sur le plan theorique et numerique l'effet des retards, dus au temps de propagation de la lumiere entre les deux miroirs. Nous montrons que les cavites utilisees pour les detecteurs d'ondes gravitationnelles presentent generalement des regimes dynamiques instables. Nous presentons quelques resultats experimentaux concernant l'alignement d'une cavite fabry-perot pendulaire au moyen de moteurs magnetiques. Dans la 2eme partie, une methode d'analyse statistique nous permet d'evaluer l'efficacite d'un reseau d'antennes gravitationnelles. Nous donnons une estimation du nombre de signaux gravitationnels detectables par differents reseaux, ainsi que du nombre de signaux detectables en coincidence par plusierus antennes. Nous comparons enfin la directivite des reseaux
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Kitano, Cláudio. « Métodos inéditos de interrogação óptica e suas aplicações na medição de grandezas físicas ». Ilha Solteira, 2016. http://hdl.handle.net/11449/149249.
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Banca: Amílcar Careli CésarBanca: Josemir Coelho Santos
Banca: Marco Isaías Alayo Chávez
Banca: Aparecido Augusto de Carvalho
Banca: Ricardo Tokio Higuti
Resumo: Neste Texto Sistematizado, o candidato a Livre Docente expõe os principais resultados alcançados em sua trajetória após o doutorado, em termos de atividades de ensino, extensão, administrativas e de pesquisa. Ênfase especial é destinada à análise crítica das atividades de pesquisa e orientação de dissertações e teses junto ao Programa de Pós-Graduação em Engenharia Elétrica - PPGEE, da FE-IS UNESP. O enfoque principal da pesquisa refere-se à proposição teórica e experimental de novas técnicas de detecção de fase óptica empregando-se interferometria laser, e suas aplicações na medição de deslocamentos microscópicos, na caracterização de atuadores piezoelétricos flextensionais e em medições de tensões elétricas elevadas. A motivação para a realização da pesquisa, a exposição dos desafios e as soluções propostas são discutidas. Inserções em outras áreas, que envolvam sensores e sistemas ópticos, bem como, a cooperação com grupos de pesquisas afins, internos e externos à FE-IS UNESP, são apresentadas. No final, discutem-se as pesquisas atuais e as perspectivas futuras
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Goltsman, Alexander Mark. « Three Dimensional Interferometric Imaging at Terahertz Frequency for Concealed Object Detection ». Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/36351.
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This project was born out of the work performed by a group of researchers at the New Jersey Institute of Technology (NJIT) [1] [2] [3] working on interferometric imaging with a spiral array. Their investigation stopped at two dimensional imaging with a two dimensional array. In this thesis, their idea was developed further into the significantly more complex imaging with a three dimensional array. The general design of the NJIT [1] [2] [3] experiment was reproduced, studied, and modified in a manner that was theorized to enhance the experiment with the added ability to perform three dimensional imaging. The NJIT team [1] [2] [3] has developed their experiment to where they were able to accurately perform two dimensional imaging of two sources of equal intensity located at different distances from a spiral array. In this thesis, the equations used for two dimensional imaging are extrapolated into a three dimensional array application. This three dimensional imaging concept is simulated with MATLAB and the results presented and compared to the NJIT experimental results. [1] [2] [3] A proof of concept physical experiment is conducted and the results are compared to the MATLAB simulation. The results show that additional spatial information can be obtained from a three dimensional array that can enhance the information gleaned from images.Master of Science
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Menezes, Jacson Weber de. « Fabricação e caracterização de estruturas periódicas utilizando superposição de padrões de interferência para aplicações em fotônica e plasmônica ». [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260707.
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Orientadores: Edmundo da Silva Braga, Lucila Helena Deliesposte CescatoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-16T22:14:56Z (GMT). No. of bitstreams: 1 Menezes_JacsonWeberde_D.pdf: 5102435 bytes, checksum: 8671ed8cf6b070b06a3270b5e81fde66 (MD5) Previous issue date: 2010
Resumo: Esta tese tem como objetivo demonstrar a viabilidade e o potencial da técnica de superposição de padrões de interferência para fabricação de estruturas periódicas 2D e 3D para aplicações em cristais fotônicos e estruturas plasmônicas. A superposição de padrões consiste em expor a mesma amostra a padrões de interferência, produzidos por duas ondas planas, girando-se a amostra apropriadamente entre as exposições. A simulação do padrão de intensidade resultante, em função do número de exposições e do ângulo de rotação entre elas, foi feita utilizando o software MATHEMATICA. Estas simulações demonstraram que com apenas 3 exposições, girando-se apropriadamente a amostra, é possível obtermos padrões com periodicidade tridimensional. As estruturas gravadas na fotorresina positiva SC 1827, utilizando esta técnica, mostraram uma excelente concordância com os padrões simulados. Embora estas estruturas não apresentem um gap fotônico completo devido ao baixo índice de refração da fotorresina, foi possível medir o gap fotônico para determinadas direções de simetria da estrutura. Camadas Finas de Cristais Fotônicos 2D com simetria triangular foram fabricadas em vidros calcogenetos a base de antimônio. As medidas da transmitância espectral em função do ângulo de incidência da luz nas diferentes direções de simetria permitiram a medida experimental do diagrama de bandas. Para os modos mais baixos as medidas experimentais mostraram uma excelente concordância com os diagramas de bandas calculados utilizando o Método dos elementos finitos (FEM). Estruturas plasmônicas, compostas por arranjos quadrados de furos em filmes de ouro foram fabricadas e caracterizadas através de medidas de transmitância à incidência normal. Devido à grande sensibilidade da posição dos picos de ressonância de plasmons com o meio, foi realizado um estudo visando a otimização dos parâmetros destas estruturas para uso como sensores de índice de refração
Abstract: The purpose of this thesis is to demonstrate the feasibility and the potential of the technique of superposition of interference patterns to generate 2D and 3D periodic structures for applications in photonic crystals and plasmonic structures. This technique consists in to expose the same sample to interference patterns produced by two plane waves, rotating properly the sample between exposures. The simulation of the resulting intensity pattern, as a function of the number of exposures and rotation angle between them, is done using the software MATHEMATICA. These simulations showed that only 3 exposures are enough to obtain three-dimensional periodic patterns. The structures recorded in SC 1827 positive photoresist, using this technique, showed excellent agreement with the simulated patterns. Although these structures do not show a complete photonic band gap because of the low refractive index of the photoresist, it was possible to measure the photonic band gap photonic for certain directions of symmetry of the structure. Thin layers of 2D Photonic Crystals with triangular symmetry were fabricated in chalcogenide glasses based on antimony. Measurements of spectral transmittance, at different incident angles in the directions of symmetry of the 2D crystal, allow obtaining the experimental band diagrams. For the lowest modes the experimental measurements agree very well with the diagrams calculated using the FEM. Plasmonic structures, composed of squared arrays of holes in gold films were fabricated and characterized through transmittance measurements at normal incidence. Due to the high sensitivity of the peak wavelength positions of plasmon resonances with the surrounding media, a study was conducted in order to optimize the parameters of these structures for refractive index sensing
Doutorado
Eletrônica, Microeletrônica e Optoeletrônica
Doutor em Engenharia Elétrica
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Zeakes, Jason S. « Extrinsic Fabry-Perot Interferometric hydrogen gas sensor ». Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06162009-063525/.
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Taylor, John R. « Interferometric experiments towards advanced gravitational wave detectors ». Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/727/.
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In 1905, Einstein postulated that the speed of light is not only finite, but that its speed in vacuum is a universal limit that no process can exceed. The Theory of General Relativity later extended this concept to include gravitational interactions, and Eddington's timely measurements of stellar positions during a solar eclipse in 1919 confirmed that gravity's effect on spacetime is both real and entirely physical -- not merely a mathematical curiosity. With the death of Newton's notions of universal time and instantaneous gravity came the idea of gravitational waves as distortions in space-time that propagate the gravitational interaction at the speed of light. These gravitational waves are emitted from any object undergoing a non-axi-symmetric acceleration of mass, but -- due to the exceptionally weak coupling between gravitational waves and matter -- are expected to induce displacements of the order of 10^-18 m in kilometre-scale detectors: the extraordinary diminutiveness of this effect has thus far precluded any direct detection of the phenomenon. Numerous gravitational wave detectors have been built since the 1960s, in the form of both interferometric detectors and resonant mass devices. Interferometric detectors currently represent the most promising form of detector, due to their relatively wide-band response to gravitational wave signals and promising levels of sensitivity. In recent years a worldwide network of these interferometric detectors (LIGO, GEO600, Virgo and TAMA300) have begun to approach (or indeed reach) their design sensitivities. Although these detectors have started to provide upper limit results for gravitational wave emission that are of astrophysical significance, there have as yet been no direct detections. As such, work is underway to upgrade and improve these detectors. However, increasing the signal sensitivity necessarily leads to an increase in their sensitivity to their limiting noise sources. Two critical noise limits that must be characterised, understood, and hopefully reduced for the benefit of future detectors, are thermal noise (from mirror substrates, reflective coatings and suspension systems) and photon noise -- associated with the intrinsic shot noise of light and the noise due to light's radiation pressure. Two interferometric experiments designed to help inform on these phenomena were constructed at the University of Glasgow's Institute for Gravitational Research. The first experiment compared the relative displacement noise spectra of two specially constructed optical cavities, to extract the thermal noise spectrum of a single test mirror. In future experiments, this optic could be changed and the thermal noise spectrum for any suitable combination of mirror substrate and reflective coating evaluated. The second experiment involved the investigation of suitable control schemes for a three-mirror coupled optical cavity. As the resonant light power in interferometers increases in future devices (in order to decrease the photon shot noise) the need to de-couple the control schemes that govern the respective cavities so that they can be controlled independently, becomes more important. As a three-mirror cavity effectively represents a simple coupled system, it provides a suitable test-bed for characterising suitable control schemes for more advanced interferometers. Together, these experiments may provide information useful to the design of future gravitational wave interferometers.
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Killbourn, Stuart Duncan. « Double pendulums for terrestrial interferometric gravitational wave detectors ». Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362943.
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Husman, Matthew Edward. « Suspension and control for interferometric gravitational wave detectors ». Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312701.
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Mavalvala, Nergis. « Alignment issues in laser interferometric gravitational-wave detectors ». Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10769.
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Buikema, Aaron. « High-power operation of interferometric gravitational-wave detectors ». Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/128328.
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This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, February, 2020
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 157-172).
With the conclusion of the first two observing runs of the Advanced LIGO detectors, which saw the first direct detection of gravitational waves, we are firmly in the era of gravitational-wave astronomy. To reach the highest sensitivities, current interferometric gravitational-wave detectors are designed for hundreds of kilowatts of circulating optical power. At these high circulating powers, the sensitivity of the detectors to gravitational waves will be limited by the quantum properties of the light: shot noise at frequencies above ~ 100 Hz, and quantum radiation pressure noise at lower frequencies. To reach the high powers necessary for achieving the quantum noise limits imposed by the light, it is essential to solve the control problems and understand the additional noise introduced by high power operation. Additionally, development of high-power laser sources that reach the stringent noise and reliability requirements is crucial. This work comprises three experiments aimed at reaching the radiation-pressure-dominated regime of interferometric gravitational-wave detectors. The first part presents results from a high-power, meter-long Fabry-Prot Michelson interferometer to probe classical and quantum radiation pressure effects using a gram-scale mechanical oscillator. The second part is an exploration of the effects of electric fields and charging of test masses on the sensitivity of the LIGO detectors, which may limit the ability to observe radiation-pressure effects. Finally, we describe the development and characterization of a high-power, narrow-linewidth ytterbium-doped fiber amplifier for use in future gravitational-wave detectors.
by Aaron Buikema.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Physics
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Rao, Shanti Raja Libbrecht Kenneth George. « Mirror thermal noise in interferometric gravitational wave detectors / ». Diss., Pasadena, Calif. : California Institute of Technology, 2003. http://resolver.caltech.edu/CaltechETD:etd-05092003-153759.
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Wise, Stacy M. « Sensitivity enhancement in future interferometric gravitational wave detectors ». [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013804.
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Nightingale, Nicholas Simon. « Stellar interferometry : detectors and the atmosphere ». Thesis, University of Cambridge, 1991. https://www.repository.cam.ac.uk/handle/1810/265401.
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The work in this disseration has arisen from the Cambridge Optical Aperture Synthesis Telescope (COAST) project. COAST is a novel stellar interferometer under construction in Cambridge, designed to obtain stellar images with an angular resolution equivalent to that of a 100m telescope. The success of this design requires innovation in a number of areas including photo-detector design. The first intention was to specify the best detector and the optimal operating wavelength for COAST. This was done by considering the signal-to-noise ratio in fringe visibility modulus measurements with various detectors. The result of these calculations and other ancillary considerations was to choose the Silicon Avalanche Photodiode (Si APD) operated in a photon counting mode. Although Si APDs have been available for several years, no commercial photon counting unit was available at the outset of this research, so having specified the parameters for the COAST detector system, research and development of a photon counting APD detector was undertaken. The result is a small self-contained unit employing an RCA APD. This unit offers exceptionally high efficiency ( 40% in the near infrared), broad spectral response and low noise whilst being rugged, reliable and reasonably cheap. These COAST detectors have a much wider range of applications than just stellar interferometry as replacements for the commonly used photomultiplier tubes, e.g. in telescope autoguiding and photometry. Atmospheric seeing is of crucial importance to the performance of stellar interferometers and large telescopes. Specifically, stellar interferometry is sensitive to a very wide range of scales in the seeing - both temporal and spatial. The well-established theoretical models of seeing are currently not well constrained experimentally, especially in relation to the outer scale of turbulence. The size of this latter parameter is the subject of debate, but is vital in determining the maximum fringe motion in an interferometer. To resolve some of these problems, a new seeing monitor (WFTI) was proposed. WFTI is a novel interferometer designed to make measurements of both the temporal and spatial scales of the seeing. It uses photon counting APD detectors for the first time in an astronomical application and was operated for two nights on the William Herschel Telescope at the La Palma Observatory (LPO ). Results verified seeing models over scales of three orders of magnitude and have shown that the underlying seeing at the LPO is exceptionally good. A direct optical detection of the outer scale was made for the first time at the LPO and may be as short as 2m. These are very promising results for future large telescopes and interferometers at the site and indicate that care must be taken with telescope design to exploit this quality of seeing to the full. Unfortunately the outer scale detection was a little more tenuous than might be wished, due to an excess of low frequency power in the data from WFTI. Possible causes (both instrumental and atmospheric) for this excess were suggested and a new instrument (WFTI II) proposed. This improved interferometer will separate instrumental from atmospheric effects by taking multiple observations concurrently. COAST path stability measurements were made using WFTI for beam combining. The results show that it will acceptable for the beams returning from the individual array elements to the optics laboratory to propagate in free air, at least with short baselines. Finally, a new method for locating the COAST "white light" fringe was described.
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Menezes, João Paulo Crivellaro de [UNESP]. « Análise teórica e experimental de um método interferométrico de detecção de fase óptica, auto-consistente e com elevada faixa dinâmica, aplicado à caracterização de atuadores piezoelétricos flextensionais ». Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/87033.
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Made available in DSpace on 2014-06-11T19:22:31Z (GMT). No. of bitstreams: 0
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menezes_jpc_me_ilha.pdf: 3284910 bytes, checksum: c8578da11e5d14cfc4d1f4eaaafb100b (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Atuadores piezoelétricos convertem energia elétrica em energia mecânica, sendo amplamente utilizados como transdutores de deslocamento micrométricos ou sub-micrométricos de elevada precisão. Neste trabalho, atuadores piezoelétricos flextensionais (APFs), projetados pelo método de otimização topológica, são caracterizados em termos de linearidade entre a tensão de excitação e o deslocamento gerado, bem como em termos de resposta em frequência, utilizando-se um interferômetro de Michelson homódino e em malha aberta. Interferômetros homódinos não realimentados têm seu desempenho prejudicado pelo fenômeno de desvanecimento, causado por perturbações ambientais espúrias que incidem aleatoriamente entre seus braços. Nesta dissertação, enfatizam-se métodos de demodulação de fase óptica baseados em relações envolvendo as componentes espectrais do sinal de saída do interferômetro que são imunes ao problema do desvanescimento. Dentre estes, destacam-se métodos clássicos como J1... J4, J1... J4 modificado, J1... J6 neg e J1... J6 pos. Estes métodos permitem a medição direta de deslocamentos microscópicos, sem a necessidade de qualquer procedimento de calibração. Além disso, não são afetados por instabilidades da fonte óptica, da responsividade do fotodiodo e da visibilidade das franjas de interferência. Contudo, apresentam reduzidas faixas dinâmicas de demodulação de fase. A fim de superar esta deficiência, investiga-se um método adicional de detecção direta, baseado na análise do espectro do sinal fotodetectado, exibindo todas as vantagens dos demais métodos, mas que é capaz de estender a faixa dinâmica de demodulação a valores tão elevados quanto 100 rad. Simulações computacionais são executadas com este método, levando-se em consideração o efeito do desvanecimento e tensões de ruído eletrônico do tipo 1/f, evidenciando...
Piezoelectric actuators convert electrical energy into mechanical energy, being widely used as micrometric or sub-micrometric displacement transducer of high accuracy. In this work, piezoelectric flextensional actuators (PFA’s), designed by the topology optimization method, are characterized in terms of linearity between the drive voltage and the corresponding displacement, as well as in terms of frequency response, using a homodyne, open-loop, Michelson interferometer. Homodyne interferometers without feedback have their performance spoiled by signal fading, caused by spurious environmental disturbances that occur randomly between their arms. This thesis emphasizes methods of optical phase demodulation, based on relations involving the spectral components of the interferometer output signal, which are immune to signal fading. Among these methods, it is detailed here the classical ones, such as J1... J4, modified J1... J4, J1... J6 neg e J1... J6 pos. These methods allow direct measurements of microscopic displacements, free of calibration procedures. Besides, they are not affected by optical source oscillations, photodiode responsivity and interferometric fringe visibility. However, they have reduced dynamic range for phase demodulation. In order to overcome this, this work investigates an additional method for direct detection, based on spectral analysis drawback of the photodetected signal. The method has all the advantages of the others, but it is able to span its demodulation dynamic range to values as high as 100 rad. Numerical simulations are done using this method (considering the signal fading and the 1/f electronic noise voltage), showing its viability to characterize PFA’s. Experiments are performed in laboratory, involving tests with different PFA’s. The method validation is carried out with the aid of an electrooptic intensity modulator, whose phase characteristics can... (Complete abstract click electronic access below)
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Heinzel, Gerhard. « Advanced optical techniques for laser interferometric gravitational wave detectors ». [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=956318886.
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Lawrence, Ryan Christopher 1975. « Active wavefront correction in laser interferometric gravitational wave detectors ». Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29308.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2003.Includes bibliographical references (p. 239-243).
As the first generation of laser interferometric gravitational wave detectors near operation, research and development has begun on increasing the instrument's sensitivity while utilizing existing infrastructure. In the Laser Interferometer Gravitational Wave Observatory (LIGO), significant improvements are being planned for installation in 2007 to increase the sensitivity to test mass displacement, hence sensitivity to gravitational wave strain, by improved suspensions and test mass substrates, active seismic isolation, and higher input laser power. Even with the highest quality optics available today, however, finite absorption of laser power within transmissive optics, coupled with the tremendous amount of optical power circulating in various parts of the interferometer, result in critical wavefront deformations which will cripple the performance of the instrument. Discussed is a method of active wavefront correction via direct thermal actuation on optical elements of the interferometer; or, "thermally adaptive optics". A simple nichrome heating element suspended off the face of an affected optic will, through radiative heating, remove the gross axisymmetric part of the original thermal distortion. A scanning heating laser- will then be used to remove any remaining non-axisymmetric wavefront distortion, generated by inhomogeneities in the substrate's absorption, thermal conductivity, etc. This work includes a quantitative analysis of both techniques of thermal compensation, as well as the results of a proof-of-principle experiment which verified the technical feasibility of each technique.
by Ryan Christopher Lawrence.
Ph.D.
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George, A. V. « Optical detectors and stellar observations in interferometry ». Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599357.
Texte intégralRésumé :
This work describes several self-contained pieces of research which are all linked by their connection with optical interferometry. First is an instrumentational project involving the selection, installation and subsequent testing of second-generation optical detectors for the Cambridge Optical Aperture Synthesis Telescope (COAST). These new detectors extended the magnitude limit of COAST by over a magnitude in the I band, increasing its range of observable astronomical targets and making it the most sensitive separate-element interferometer in this band. Also described were two observational projects. The first was carried out using COAST and was made possible by the improved sensitivity of the instrument after installation of the new detectors. It involved observations of two Be stars, Gamma Cassiopeiae and Zeta Tauri, in a narrow Hα band. Non-zero closure phases were measured in both cases, indicating deviations from axisymmetry in the circumstellar discs of the two stars. The first true map of Gamma Cassiopeiae was presented. The second observational project involved measurements of the proto-planetary nebula IRC+10216 made with the UK InfraRed Telescope (UKIRT), using the interferometric technique of speckle masking to achieve close to diffraction-limited imaging. The results include the first ever K-L map and K-band polarisation map of this source. From these and other observations, we found evidence that the morphology of the complex inner dust cloud differs from the models suggested by most other authors, and the star is completely obscured in both the K and L bands.
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Killow, Christian J. « Interferometry developments for spaceborne gravitational wave detectors ». Thesis, University of Glasgow, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426535.
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Rýc, Jan. « Michelsonův interferometr ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218901.
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The diploma work deals with techniques of optical contactless distance and velocity measurement. A basic summary of the methods are involved. The problematic of interferometric methods for vibration measurements is analysed in detail. It contains division of interferometers, description of their function principles and also chapters dealing with elements used in interferometers such as lasers, photodetectors and elements in the ray optical way - polarizers, retarders, optical isolators. The vibration and length measurement methods are described, as well as the conception of homodyne and heterodyne detection. Part of this work focuses on the quadrature signal processing and on the proposal of algorithm for demodulation of velocity/displacement and undergoing simple motioning object deviation. This algorithm is implemented in Labview and the whole software instrument served also for visualisation of measured data of the interferometer model constructed in the laboratory. The way how to build up a model, its setting and two possible configurations suitable for homodyne detection are described. Model of interferometer is built-up on the optical breadboard. Particular components are fixed by the help of mounts. The model and software enable to measure the velocity and the vibration deviation with the light wavelength exactness. Functionality and the exactness of the laboratory model are verified by vibrometer. Effects on the measurement uncertainty are discussed here and ways how to restrain them are proposed.
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Casey, Morag Margaret. « Developments towards autonomous operation of laser interferometric gravitational wave detectors ». Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300656.
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Fotopoulos, Nickolas. « Searching for stochastic gravitational waves using co-located interferometric detectors ». Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/39567.
Texte intégralRésumé :
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.Includes bibliographical references (p. 83-85).
Despite their intrinsic advantages due to co-location, the two LIGO (Laser Interferometer Gravitational Wave Observatory) Hanford interferometers have not been used in the search for the stochastic gravitational wave background due to their coupling to a shared environment, which may be comparable to or exceed any gravitational signal. In this thesis, using data from LIGO's fourth science run, we demonstrate a technique to relate the H1-H2 coherence to coupling with physical environmental channels. We show that the correspondence is tight enough to correctly identify regions of high and low coupling and the nature of the coupling in the data set. A simple thresholding provides frequency vetoes, which we can use to derive a significantly cleaner coherence spectrum. Next, using this frequency veto technique and data from the first epoch of LIGO's fifth, currently running science run, we design, implement, and perform a search for astrophysical populations of gravitational wave emitters, which emit predominantly in the kilohertz region of the spectrum, a region totally inaccessible to detectors separated by thousands of kilometers. As well as providing us with a proof-of-concept, the results provide an advanced look at the physical results to come from H1-H2 by the end of S5.
by Nickolas Fotopoulos.
S.M.
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Leavey, Sean Stephan. « Enhancing the sensitivity of future laser-interferometric gravitational wave detectors ». Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/7902/.
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The first direct detection of gravitational waves last year was the beginning of a new field of astronomy. While we have already learned a great deal from the signals sensed by the LIGO interferometers in their first observation run, research is already underway to improve upon the sensitivity of the state of the art detectors. Novel mirror designs, new interferometer topologies and larger, more advanced detectors are all being considered as future improvements, and these topics form the focus of this thesis. A reduction in the thermal noise arising from the mirrors within gravitational wave detectors will enhance sensitivity near their most sensitive frequencies, and this can potentially be achieved through the use of waveguide mirrors employing gratings. It has been shown that the thermal noise is reduced in waveguide mirrors compared to standard dielectric mirrors whilst retaining the required reflectivity, but an open question regarding their suitability remains due to the potential for increased technical noise coupling created by the substructure. We place an upper limit on this coupling with a suspended cavity experiment, showing that this approach to the design of grating mirrors has promise. While the use of higher classical laser input initially increases interferometer sensitivity, eventually the Michelson interferometer topology employed in existing detectors reaches the standard quantum limit preventing further enhancement. Efforts are being made to test the suitability of so-called quantum non-demolition (QND) technologies able to surpass this limit, one of which involves the use of a new interferometer topology altogether. An experiment to demonstrate a reduction in quantum radiation pressure noise in a QND-compatible Sagnac speed meter topology is underway in Glasgow, and we introduce novel techniques to control this suspended, audio-band interferometer to inform the technical design of future detectors wishing to measure beyond the standard quantum limit. In particular, the problem of controlling the interferometer at low frequencies is discussed. Due to the nature of the speed meter topology, the response of the interferometer vanishes towards zero frequency, while the interferometer's noise does not. This creates a control problem at low frequencies where test mass perturbations arising from, for example, seismic and electronic noise, can lead to loss of interferometer sensitivity over the course of minutes to hours. We present a solution involving the blending of signals from different readout ports of the interferometer, facilitating measurements with almost arbitrary integration times. The longer, larger Einstein Telescope facility planned as part of the next generation of detectors will push the Michelson interferometer topology to the limit. The low frequency interferometer will utilise optomechanical interactions to enhance its sensitivity at low frequencies, and the control problems associated with this technique have not been investigated in detail. Following the approach taken in the current generation of detectors we show that the interferometer can be controlled without adversely affecting its sensitivity to gravitational waves, paving the way for a future technical design.
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Shaddock, Daniel Anthony, et Daniel Shaddock@jpl nasa gov. « Advanced Interferometry for Gravitational Wave Detection ». The Australian National University. Faculty of Science, 2001. http://thesis.anu.edu.au./public/adt-ANU20020227.171850.
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In this thesis we investigate advanced techniques for the readout and control of various interferometers. In particular, we present experimental investigations of interferometer configurations and control techniques to be used in second generation interferometric gravitational wave detectors. We also present a new technique, tilt locking, for the readout and control of optical interferometers.
¶
We report the first experimental demonstration of a Sagnac interferometer with resonant sideband extraction (RSE). We measure the frequency response to modulation of the length of the arms and demonstrate an increase in signal bandwidth of by a factor of 6.5 compared to the Sagnac with arm cavities only. We compare Sagnac interferometers based on optical cavities with cavity-based Michelson interferometers and find that the Sagnac configuration has little overall advantage in a cavity-based system.
¶
A system for the control and signal extraction of a power recycled Michelson interferometer with RSE is presented. This control system employs a frontal modulation scheme requiring a phase modulated carrier field and a phase modulated subcarrier field. The system is capable of locking all 5 length degrees of freedom and allows the signal cavity to be detuned over the entire range of possibilities, in principle, whilst maintaining lock. We analytically investigate the modulation/demodulation techniques used to obtain these error signals, presenting an introductory explanation of single sideband modulation/demodulation and double demodulation.
¶
This control system is implemented on a benchtop prototype interferometer. We discuss technical problems associated with production of the input beam modulation components and present several solutions. Operation of the interferometer is demonstrated for a wide range of detunings. The frequency response of the interferometer is measured for various detuned points and we observe good agreement with theoretical predictions. The ability of the control system to maintain lock as the interferometer is detuned is experimentally demonstrated.
¶
Tilt locking, a new technique to obtain an error signal to lock a laser to an optical cavity, is presented. This technique produces an error signal by efficient measurement of the interference between the TEM00 and TEM10 modes. We perform experimental and theoretical comparisons with the widely used Pound-Drever-Hall (PDH) technique. We derive the quantum noise limit to the sensitivity of a measurement of the beam position, and using this result calculate the shot noise limited sensitivity of tilt locking. We show that tilt locking has a quantum efficiency of 80%, compared to 82% for the PDH technique.
We present experimental demonstrations of tilt locking in several applications including frequency stabilisation, continuous-wave second harmonic generation, and injection locking of a Nd:YAG slab laser. In each of these cases, we demonstrate that the performance of tilt locking is not the limiting factor of the lock stability, and show that it achieves similar performance to the PDH based system.
¶
Finally, we discuss how tilt locking can be effectively applied to two beam interferometers. We show experimentally how a two beam interferometer typically gives excellent isolation against errors arising from changes in the photodetector position, and experimentally demonstrate the use of tilt locking as a signal readout system for a Sagnac interferometer.
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Dennis, Karla Ann. « Characterization of HFAPNB and PHOST as a polymer sensing layer in an interferometric evanescent wave sensor ». Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29682.
Texte intégralRésumé :
Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Henderson, Clifford L.; Committee Member: Ludovice, Pete; Committee Member: Ralph, Stephen E.. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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STAHL, HARLOW PHILIP. « INFRARED PHASE-SHIFTING INTERFEROMETRY USING A PYROELECTRIC VIDICON (TESTING, FABRICATION) ». Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187965.
Texte intégralRésumé :
The increased demand for modern optical components necessitates an interferometric system that can rapidly and accurately measure wavefront phase errors during the complete fabrication process, from generation to polishing. The suitability of infrared wavelengths for several optical testing applications is well known, as are the greatly increased speed and accuracy of phase-shifting interferometric techniques. Therefore, this dissertation discusses extensively three topics: (1) the demonstration theoretically and experimentally of the feasibility of using a pyroelectric vidicon for infrared phase-shifting interferometry, (2) the design and fabrication of a prototype next-generation optical shop infrared phase-shifting interferometric system, and (3) the definition and quantification of the fundamental system performance parameters and limitations. Additionally, some application examples of infrared phase-shifting interferometry are presented, and specific recommendations for future work are included with the conclusions.
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Fattaccioli, Dominique. « Etudes theoriques sur les interferometres pour la detection des ondes de gravitation ». Paris 6, 1987. http://www.theses.fr/1987PA066366.
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D'une part, nous caracterisons la reponse des interferometres de michelson a une onde de gravitation en derivant analytiquement les expressions de leurs fonctions de transfert et de leurs fonctions de green et en explicitant la dependance de celles-ci envers les parametres de l'onde de gravitation, ce travail etant a la base de toute methode d'analyse des donnees d'une grande antenne interferometrique. D'autre part, nous etudions certaines limitations de ces instruments de haute precision que sont les interferometres, dans le but de definir les specifications technologiques des differents elements optiques les constituant qui devront etre satisfaites pour la detection des ondes de gravitation
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Degallaix, Jerome. « Compensation of strong thermal lensing in advanced interferometric gravitational waves detectors ». University of Western Australia. School of Physics, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0060.
Texte intégralRésumé :
A network of laser interferometer gravitational waves detectors spread across the globe is currently running and steadily improving. After complex data analysis from the output signal of the present detectors, astrophysical results begin to emerge with upper limits on gravitational wave sources. So far, however no direct detection has been announced. To increase the sensitivity of current detectors, a second generation of interferometers is planned which will make gravitational wave astronomy a reality within one decade. The advanced generation of interferometers will represent a substantial upgrade from current detectors. Especially, very high optical power will circulate in the arm cavities in order to reduce by one order of magnitude the shot noise limited sensitivity in high frequency. However, the theoretical shot noise limit will only be achieved after implementation of complex thermal lensing compensation schemes. Thermal lensing is direct consequence of the residual optical absorption inside the substrate and coating of the test masses and could have tragic consequences for the functionality of the interferometer. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) in collaboration with LIGO will run a series of high optical power tests to understand the characteristics and effects of thermal lensing. During these tests, techniques to compensate thermal lensing will be experimented. This thesis mainly focused on the first high optical power test in Gingin, Australia. The first test will consist of a Fabry Perot cavity with the sapphire substrate of the input mirror inside the cavity. Due to the high optical circulating power a strong convergent thermal lens will appear in the input mirror substrate. Because of the presence of the thermal lens inside the cavity, the size of the cavity waist will be reduced and the cavity circulating power will decrease. Simulations using higher order mode expansion and FFT propagation code were completed to estimate ways to compensate strong thermal lensing for the Gingin first test. The term `strong thermal lensing? is used because the thermal lens focal length is comparable to the design focal length of the optical components. The expected performance of a fused silica compensation plate is presented and advantages and limits of this method are discussed. Experimental results on small scale actuators which can potentially compensate thermal lensing are detailed. The knowledge gained from these experiments was valuable to design the real scale compensation plate which was used in the first Gingin test. This test was carried at the end of 2005. The thermal lens due to 1 kW of optical power circulating in the sapphire substrate was successfully compensated using a fused silica plate. Yet, thermal lensing compensation may only be required for room temperature advanced interferometer. Indeed, we showed that cooling the interferometer mirror to cryogenic temperature can eliminate the thermal lensing problem and also substantially decrease the mirror thermal noise.
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Martin, Iain William. « Studies of materials for use in future interferometric gravitational wave detectors ». Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/1517/.
Texte intégralRésumé :
Gravitational waves, predicted by the theory of General Relativity, are fluctuations in the curvature of space-time which arise from the asymmetric acceleration of mass. While gravitational waves have yet to be detected directly, measurements of the inspiral rate of a binary pulsar system have provided strong evidence for their existence and a world-wide effort to develop more sensitive detectors is ongoing. In addition to testing predictions of General Relativity, observation and analysis of gravitational waves from astrophysical sources will provide new insights into a wide range of phenomena including black holes, neutron stars and supernovae. Gravitational waves are quadruple in nature, and therefore produce fluctuating tidal strains on space. Long baseline gravitational wave detectors aim to measure this effect using laser interferometry to measure fluctuations in the relative separation of free masses, coated to form highly reflective mirrors and suspended as pendulums at the ends of perpindicular arms up to 4 km in length. There are currently several long baseline gravitational wave detectors in operation around the world, including the three LIGO detectors in the US, the UK/German GEO600 detector near Hannover and the French/Italian Virgo detector near Pisa. The strain expected from gravitational waves is very small, of order [~10-[superscript 22. The magnitude of the resultant displacement is such that the thermal motion of the mirrors and their suspensions forms an important limit to detector sensitivity. The level of thermal noise is related to the mechanical dissipation of the materials used in the test mass and the mirror coatings.
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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/.
Texte intégralRésumé :
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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Twyford, Sharon Melanie. « Developments towards low mass suspension for laser interferometric gravitational wave detectors ». Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285038.
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Goda, Keisuke. « Development of techniques for quantum-enhanced laser-interferometric gravitational-wave detectors ». Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/45405.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (p. 213-225).
A detailed theoretical and experimental study of techniques necessary for quantum-enhanced laser- interferometric gravitational wave (GW) detectors was carried out. The basic theory of GWs and laser-interferometric GW detectors, quantum noise in GW detectors, the theory of squeezed states including generation, degradation, detection, and control of squeezed states using sub-threshold optical parametric oscillators (OPOs) and homodyne detectors, experimental characterization of these techniques (using periodically poled KTiOPO4 in an OPO at 1064 nm for the first time), key requirements for quantum-enhanced GW detectors, and the propagation of a squeezed state in a complex interferometer and its interaction with the interferometer field were studied. Finally, the experimental demonstration of quantum-enhancement in a prototype GW detector was performed. By injecting a squeezed vacuum field of 9.3 dB (inferred) or 7.4 ± 0.1 dB (measured) at frequencies above 3 kHz and a cutoff frequency for squeezing at 700 Hz into the antisymmetric port of the prototype GW detector in a signal-recycled Michelson interferometer configuration, the shot noise floor of the detector was reduced broadband from 7.0 x 10-7 m/viH- to 5.0 x 10-17 m/V/H while the strength of a simulated GW signal was retained, resulting in a 40% increase in signal-to-noise ratio or detector sensitivity, which is equivalent to a factor of 1.43 = 2.7 increase in GW detection rate for isotropically distributed GW sources that are confined to the frequency band in which squeezing was effective. This is the first implementation of quantum-enhancement in a prototype GW detector with suspended optics and readout and control schemes similar to those used in LIGO and Advanced LIGO. It is, therefore, a critical step toward implementation of quantum-enhancement in long baseline GW detectors.
by Keisuke Goda.
Ph.D.
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Carolan, Thomas Andrew. « Acoustic emission detection by fibre optic interferometry ». Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1419.
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Zhu, Yunlong. « Exploration of Interferometric Detection Methods based on Continuous Phase Modulation ». Thesis, Troyes, 2018. http://www.theses.fr/2018TROY0024.
Texte intégralRésumé :
Dans cette thèse, nous nous intéressons aux signaux interférométriques à modulation de phase continue, dans le but de développer des dispositifs de détection performants et originaux pour des applications en mécanique et en optique. Nous présentons d'abord plusieurs des techniques de modulation et démodulation employées dans ce contexte. Nous nous focalisons sur les modulations de phase sinusoïdales (SPM), qui sont particulièrement avantageuses pour les dispositifs de modulation les plus largement accessibles. Nous proposons alors des solutions au problème de synchronisation ainsi qu'au problème éventuel de modulation d'amplitude concomitante à la modulation SPM. Ces techniques de démodulations sont ensuite appliquées à 3 dispositifs expérimentaux développés au cours de cette thèse. Il s'agit d'abord d'un dispositif d'holographie digitale compact sans lentille, mettant en œuvre une modulation SPM simple, pour l'imagerie et la mesure de déplacement. Nous utilisons ensuite une technique de modulation à double fréquence pour réaliser des mesures bidimensionnelles de champ de déformation, à l'aide d'un dispositif ESPI (interférométrie de speckle) original. Cette approche permet une mesure simultanée dans les 2 directions du plan à l'aide d'un seul système de laser et caméra. Finalement, nous présentons un instrument de type SPR (Surface Plasmon Resonance) compact mettant en œuvre une détection interférométrique SPM par modulation de longueur d'onde, dans lequel la modulation d'amplitude est prise en compte avec succèsIn this thesis, interference signals with continuous phase modulations are theoretically and experimentally analyzed in order to develop cost-efficient solutions for sensing application in mechanics and optics.Several common phase modulation functions and phase retrieval algorithms are presented. We mainly focus on sinusoidal phase modulation (SPM), which is especially attractive for the most accessible modulators (e.g. electro-optical or piezoelectrical modulators). In such case, the demodulation process must handle synchronization issue as well as a possible intensity modulation induced by the SPM. Mathematical solutions are proposed in this context. These demodulation techniques are then applied to three experimental devices developed during this thesis. First of all, a lens-less co-axis digital holography setup has been built, and SPM has been applied for imaging and displacement measurement. Then we use a dual-frequency modulation technique to perform two-dimensional deformation field measurements using an original ESPI (Electronic Speckle Pattern Interferometry) device. This approach allows for simultaneous measurement of the displacement along two different axes using a single laser and a single camera. Finally, we present a compact SPR (Surface Plasmon Resonance) instrument implementing SPM interferometric detection through wavelength modulation, where the amplitude modulation is successfully taken into account
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Nuñez, P. D., N. J. Scott, B. Mennesson, O. Absil, J. C. Augereau, G. Bryden, Brummelaar T. ten et al. « A near-infrared interferometric survey of debris-disc stars ». EDP SCIENCES S A, 2017. http://hdl.handle.net/10150/626407.
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We report the results of high-angular-resolution observations that search for exozodiacal light in a sample of main sequence stars and sub-giants. Using the "jouvence" of the fiber linked unit for optical recombination (JouFLU) at the center for high angular resolution astronomy (CHARA) telescope array, we have observed a total of 44 stars. Out of the 44 stars, 33 are new stars added to the initial, previously published survey of 42 stars performed at CHARA with the fiber linked unit for optical recombination (FLUOR). Since the start of the survey extension, we have detected a K-band circumstellar excess for six new stars at the similar to 1% level or higher, four of which are known or candidate binaries, and two for which the excess could be attributed to exozodiacal dust. We have also performed follow-up observations of 11 of the stars observed in the previously published survey and found generally consistent results. We do however detect a significantly larger excess on three of these follow-up targets: Altair, v And and kappa CrB. Interestingly, the last two are known exoplanet host stars. We perform a statistical analysis of the JouFLU and FLUOR samples combined, which yields an overall exozodi detection rate of 21.7(-4.1)(+5.7) %. We also find that the K-band excess in FGK-type stars correlates with the existence of an outer reservoir of cold (less than or similar to 100 K) dust at the 99% confidence level, while the same cannot be said for A-type stars.
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McNamara, Paul William. « Development of optical techniques for space-borne laser interferometric gravitational wave detectors ». Thesis, University of Glasgow, 1998. http://theses.gla.ac.uk/8477/.
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This thesis deals with aspects of gravitational wave detection relating directly to the proposed LISA mission. The thesis begins with a review of gravitational wave astrophysics, starting with a brief description of the prediction and nature of gravitational radiation as a consequence of General Relativity. A short description of possible astrophysical sources is given along with current estimates of signal sources and strengths. The history of gravitational wave detectors is then briefly outlined, from the early 1960s and the first resonant bar, through to the modern long baseline laser interferometers currently under construction. Discussion then turns to the joint ESA/NASA space-borne interferometer, LISA. LISA involves picometre precision laser interferometry between spacecraft separated by millions of kilometres. Among the considerable technical challenges involved are the need for laser and clock frequency stabilisation schemes, active phase-locked laser transponders and precision telescope design. After an overview of the mission concept, the thesis deals with the issue of gravitational wave signal extraction from the various interferometric data streams produced in the six LISA spacecraft. A scheme for obtaining the necessary transfer of clock stability around the set of spacecraft is presented. LISA is planned to use diode-pumped solid state lasers. Experiments carried out to characterise the frequency noise of such a laser over the timescales of interest to the LISA mission are then described. Active frequency stabilisation to a triangular Fabry-Perot reference cavity is undertaken, with independent measurements of residual frequency noise obtained from a second analyser cavity. In LISA, the divergence of the laser beams as they propagate along the long arms of the interferometer means that only a very small amount of light is received by any spacecraft. The phase locking system has to function with this low received intensity and should, ideally, produce a transponded beam with relative phase fluctuations determined by the photon shot noise of the weak received light. A test and demonstration of the phase-locked laser transponder scheme for LISA is then presented. The frequency stabilised laser is used as the master oscillator, and a second identical laser is used as the slave. Results are obtained both from within the stabilisation system and also from out-of-Ioop measurements using an independent optical path. At relative power levels approaching those in LISA, performance close to the shot noise limit was demonstrated over part of the frequency spectrum of interest. Some excess noise was, however, found at milliHertz frequencies, most probably due to thermal effects. The thesis then continues with an investigation of far-field wavefront aberrations caused by errors in the transmitting telescopes originally planned for LISA. Any phase variation across the near field wavefront (defined as the wavefront on the primary mirror), caused, for example, by a mis-alignment of the telescope mirrors, will produce phase variation in the far-field wavefront. Coupled with pointing fluctuations of the incoming light, these wavefront distortions can cause excess displacement noise in the interferometer readout. The starting point of the investigation was to redesign the LISA telescope in order to remove both spherical and coma aberrations. Using Gaussian ray tracing techniques, the effect of near field aberrations on the far field phase was explored. A revised Ritchey-Chretien telescope design is described and numerical simulations presented. Finally the thesis concludes with a summary of the work carried out, setting the results in the context of the development of the LISA mission.
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Schütte, Dirk [Verfasser]. « Modern control approaches for next-generation interferometric gravitational wave detectors / Dirk Schütte ». Hannover : Technische Informationsbibliothek (TIB), 2016. http://d-nb.info/1118739361/34.
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Palmer, David Andrew. « Modelling and control of suspensions as used in interferometric gravitational wave detectors ». Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394956.
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Green, Anna Catriona. « When light gets pushy : radiation pressure effects in interferometric gravitational wave detectors ». Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8512/.
Texte intégralRésumé :
Advanced LIGO made the first direct observation of a gravitational wave in 2015. This signal, the largest measured so far, had a peak strain amplitude of 1 x 10-21 and frequency range 35-250 Hz. LIGO's sensitivity was achieved after decades of development. Suspended optics made from low-loss materials are employed in an optical configuration with multiple coupled cavities to increase the circulating power and shape the frequency response of the detector. This design results in radiation pressure that substantially alters the detector's behaviour. One challenging consequence is parametric instabilities, an unstable coupling between the optical field and mechanical resonances in the mirrors. My detailed investigations of parametric instabilities in both LIGO and ET, a planned next-generation detector, show that the severity of the instabilities depends on the complete optical configuration. With this model, an optimal operating point for LIGO can be determined and ET design choices can be weighed against potential instabilities. An 'optomechanical filter' has been proposed that uses radiation pressure to enhance the detector bandwidth. I test the analytical models against numerical simulations and outline an experimental research programme that will implement a trial filter.