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 19 of 19 for “"optical interference"”.
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Electrostatic Self-Assembly of Linear and Nonlinear Optical Thin Films
… (ESA) methods to fabricate linear and nonlinear optical thin films and components. The ESA process involves the layer-by-layer alternate adsorption of anionic and cationic complexes from aqueous solutions. Selection of the molecules in each layer, their orientation at the molecular level, and the …
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Imbedded optical fiber sensor of differential strain and temperature in graphite/epoxy composites
A novel optical fiber sensor for the measurement of strain and temperature in graphite-epoxy composite materials using differential interferometry is described. The sensor uses two single-mode optical fiber waveguides imbedded within the composite during prepreg ply lay-up. Strain and temperature …
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Experimental investigations of the pretransition behavior near the nematic-smectic A phase transition
… to distort the liquid crystal and a sensitive optical interference technique to measure the distortion. Both measurements are performed with millikelvin temperature resolution and yield critical exponents for the elastic constants and the twist viscosity coefficient. These results are …
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Electromagnetically induced transparency by NMR
… Transparency (EIT) is a quantum nonlinear optical interference effect in which light at a certain frequency makes normally opaque atomic systems transparent to light at another frequency. Recent experiments in Atomic Molecular and Optical (AMO) physics demonstrated how the EIT effect can be …
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Linear Optical Thin Films Formed by Electrostatic Self-Assembly
… coatings. The feasibility of fabricating linear optical interference filters by ESA methods is demonstrated in this thesis work. Basic single-anion/single-cation ESA films are synthesized and their optical parameters -- refractive index and average thickness for individual bilayer -- are …
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Design of a MEMS-based optical accelerometer with large measurable range and high sensitivity
… sensitivity, etc. In this thesis, a MEMS-based optical accelerometer is designed and analyzed. The device can be fabricated on a silicon-on-insulator (SOI) wafer, on which a double-leg single-mode optical rib waveguide is used to propagate 1.55μm laser beam. The device integrates the waveguide …
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Sputtering fabrication of silicon nitride and silicon oxide based dichroic mirrors
Thin films in optical materials utilize the properties of multiple materials to obtain specific and fine-tuned transmission, absorption and reflectance at wavelengths. Dichroic mirrors exhibit very different reflectance and transmission rates at certain cut-off wavelengths, which can be adjusted …
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Nanostructural engineering of vapor-processed organic photovoltaics for efficient solar energy conversion from any Surface
… of multijunction efficiency via computational optical interference modeling and subcell photocurrent balance quantization and control, and (2) novel implementation of conventional vapor processing methods in the formation of molecular semiconductor crystals. This work has confirmed the …
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Indium phosphide based integrated photonic devices for telecommunications and sensing applications
… and medicine. In particular, an integrated all-optical logic gate and wavelength converter for fiber-optic telecommunications and an integrated tunable laser for trace-gas sensing are investigated in this thesis. These devices are fabricated in the indium phosphide (InP) material system, which …
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Diffractive electron mirror for use in quantum electron microscopy
… gratings with tetrode electron mirrors. Optical interference lithography was used to fabricated silicon diffraction gratings with pitches varying from 200 nm to 500 nm. Furthermore, a proof-of-principle experiment to demonstrate their function as electron mirrors inside a scanning …
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Optical Coherence Sensors in Multimode Fibers
Optical fiber sensors are widely applied in modern sensing systems. Taking advantage of the high sensitivity of optical interference, optical coherence fiber sensors, such as fiber Bragg gratings (FBGs) and Fabry-Perot interferometers (FPIs), have been investigated intensively and utilized broadly …
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Development of Novel Optical Fiber Interferometric Sensors with High Sensitivity for Acoustic Emission Detection
… a new highly-sensitive and reliable fiber optical acoustic sensor capable of real-time on-line detection of acoustic emissions in power transformers, this dissertation presents the comprehensive research work on the theory, modeling, design, instrumentation, noise analysis, and performance …
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Studies of Bitumen Aeration
… camera has been developed to record the optical interference patterns of the wetting films formed on a flat surface and subsequently obtain the temporal and spatial profiles of the films offline using the Reynolds lubrication theory. The technique has been used to study the interaction …
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Fourier Transform Interferometry for 3D Mapping of Rough and Discontinuous Surfaces
Of the wide variety of existing optical techniques for non-contact 3D surface mapping, Fourier Transform Interferometry (FTI) is the method that most elegantly combines simplicity with high speed and high resolution. FTI generates continuous-phase surface maps from a projected optical interference …
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Sapphire Fiber Optic Sensor for High Temperature Measurement
… thermal radiation field. The radiation-induced optical interference pattern was observed. We demodulated the temperature sensor by white-light-interferometry (WLI). Temperature resolution better than 1°C was achieved. Chapter 3 discusses a novel approach to demodulate an optical F-P cavity at …
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Surface and Hydrodynamic Forces in Wetting Films
… of unstable wetting films by recording the optical interference patterns. The kinetic information derived from the spatiotemporal profiles were then used to determine the disjoining pressures using an analytical expression derived in the present work on the basis of the Reynolds lubrication …
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Adsorption in Confined Aqueous Films
… Debye-length. The separation was measured using interference microscopy and the adsorption of fluorescein was measured using fluorescence microscopy. The Debye-length was altered by variation of the background salt (NaCl) concentration in dilute (<1 M) solution. The surface excess of adsorption …
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Design of Multilayer Optical Media: Organic Photovoltaics and Optical Data Storage
The optical properties of one-dimensional layered materials provides a wealth of interesting phenomena. Fine control of the optical properties of the constituent materials and the thicknesses of each layer allows for sophisticated design of useful optical devices. Optical devices based on …
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Efecto de los recubrimientos ungueales sobre la precisión de la pulsioximetría en adultos sanos: estudio piloto
La pulsioximetría es una herramienta fundamental para la monitorización no invasiva de la saturación de oxígeno periférica (SpO₂); sin embargo, la posible interferencia de recubrimientos ungueales como esmaltes y uñas acrílicas continúa siendo motivo de debate en la práctica clínica. Este estudio …