Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"Fringe Visibility"”.
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Propagation of Gaussian Beams Through a Modified von Karman Phase Screen
… scintillation index for a single beam and on the fringe visibility for the two transversely separated beams. We use the modified von Karman spectrum model to describe the phase screen statistics, utilizing the Fried parameter, inner scale and the outer scale. The scintillation index is analyzed as …
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Theoretical and Experimental Study of Low-Finesse Extrinsic Fabry-Perot Interferometric Fiber Optic Sensors
… processing of white-light SMF-EFPI systems. Fringe visibility degradation due to gap-length increase and sensor imperfections is studied. The results indicate that the fringe visibility of a SMF-EFPI sensor is relatively insensitive to the gap-length change and sensor imperfections. Based on …
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Applications of correlated photon pairs : sub-shot noise interferometry and entanglement
… noise limit, although the current interference fringe visibility of [beta]= 0.84 ± 0.04 only translates to a shot noise limited phase uncertainty. Polarization-time entangled pairs can also be directly generated, by optically pumping the atoms to both F = 3, mF = ±3 ground states. The degree of …
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Adaptive Optics for Stellar Interferometry
… to achieve the final goal: reduced losses in fringe visibility and increased sensitivity. The thesis is organised with the second chapter discussing the theory of seeing phase aberrations; their origin and effect on image resolution and fringe visibility. These are used to quantify and compare …
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Study of Multimode Extrinsic Fabry-Perot Interferometric Fiber Optic Sensor on Biosensing
… for the thin-film measurement due to the high fringe visibility. However, compared with a SMF sensor system, a multimode fiber (MMF) sensor system is lower-cost and has larger sensing area (the fiber core), providing the potential for higher sensing efficiency. In this thesis, a multimode …
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Fabry-Perot Sapphire Temperature Sensor for Use in Coal Gasification
… a solid cladding for sapphire fiber, improved fringe visibility sapphire wafers and a new sensor design. This project is supported by the National Energy and Technology Laboratory of the Department of Energy.
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A rapidly scanning three-velocity-component laser Doppler anemometer
… optical system allows for easy variation of the fringe spacings as well as the location and the size of the measurement volume. The optical paths are equalized without use of any additional optical components. A Ronchi Ruling is employed to create a horizontal stationary fringe pattern, and a …
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Modeling and Signal Processing of Low-Finesse Fabry-Perot Interferometric Fiber Optic Sensors
… single-mode and multimode fiber based EFPIs. The fringe visibility and the additional phase in the spectrum are found to be strongly influenced by the optical path difference (OPD), the output spatial power distribution and the working wavelength; however they are not directly related to the light …
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Optical Fiber Fabry-Perot Interferometer based Sensor Instrumentation System for Low Magnetic Field Measurement
… sensor gage endface demonstrates 92 percent of fringe visibility, which further improves the performance of the interferometer. The signal fading in the interferometric sensors at the peak or bottom of a fringe is reduced by using a quadrature signal demodulation method. The system has been …
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157nm F₂laser characterization and application to polymer ablation
… These cones produce a circular interference fringe system with submicron period adjacent to their base as a result of walls reflections. An ablation model is used to analyse these fringes, and from the range of fringe visibility it is shown possible to estimate the spatial coherence …
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NONDESTRUCTIVE EVALUATION USING REAL-TIME SHEAROGRAPHY
… effective technique for determining fractional fringe order is also another primary objective in this project. The principle behind the formation of high resolution "live" fringe patterns by real-time shearography is presented. It is shown that both linear and nonlinear photographic recordings …
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Development of an automated alignment system for the Magdalena Ridge Observatory Interferometer
… beam combining laboratory that houses the fringe tracker and science instruments. One major improvement of the MROI over contemporary interferometers is its aim to track fringes on targets as dim as magnitude 14 in the H band, which will unlock more of the night sky for high resolution …
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Quantitative Anisotropy Imaging based on Spectral Interferometry
… In this work, a dual-modality phase/birefringence imaging system is proposed to offer a quantitative approach to characterize phase, polarization and spectroscopy properties on a variety of samples. An interferometric spectral multiplexing method is firstly introduced by generating …
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Stellar interferometry - detectors and the atmosphere.
… 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 …