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 20 of 52 for “"optical quality"”.
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Engineering the optical quality of quantum emitters in WSe₂
… quantum computing. This thesis focusses on the optical properties of these emitters, and how we can improve them through device engineering and alternative excitation regimes. In this thesis, I demonstrate devices with optimised design to produce stable emitters leading to reduced spectral …
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The deformation of large telescope mirrors and optical quality
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 1996.
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Study of Cavity Geometry to Improve Optical Quality of Windows in Hypersonic Flow
The optical quality of the window-air system of a flight vehicle in hypersonic flow is simulated. The optical distortion of the window-air system is the metric of merit. Within the earth’s atmosphere, vehicles at hypersonic speeds may generate viscous and high-temperature thermal boundary layers. …
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Characterization of as-grown and annealed narrow band gap nitrides grown by molecular beam epitaxy
… to supplant existing material systems used for optical fiber communications. While the field is relatively new, significant device advancements have occurred. These improvements have been driven by experimental advances in growing high quality material. The rush for device improvement has left …
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A human factors evaluation of selected touch entry devices
… I consisted of the quantification of CRT-TED optical quality involving photometric measurements. Phase II involved the measurement and analysis of interactive operator performance in three generic tasks. Phase II was followed by the recording of subjective assessments of TED utility (Phase …
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Synthesis and characterization of transparent conducting oxides for Stark e ect applications in single molecule spectroscopy
… this mechanism requires a Stark cell. The high optical quality required by the SMS procedure demands a very speci c thickness microscope slide at the objective to sample interface. Since no commercial TCOs of this standard were available, we had to synthesize our own and spincoat our SMS setup's …
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Study of the Morphology and Optical Properties of Propylene/Ethylene Copolymer Films
… This work investigated the morphology and optical properties of cast and compression molded films made from the homopolymer and copolymers with up to 20 mol% ethylene comonomer. The defect distribution of the Dow Chemical copolymers resulted in materials with lower crystallinity than …
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Fabrication and Characterization of Three Dimensional Photonic Crystals Generated by Multibeam Interference Lithography
… templates. In this research, optimization of the optical setup and the photoresist initiation system leads to a significant improvement of the optical quality of the crystal, as characterized by normal incidence optical spectroscopy. Theoretical spectra are calculated and demonstrate close …
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Additive manufacturing of glass using a filament fed process
… transparent glass parts. The special thermal and optical properties of glasses make them hard to be printed using conventional AM techniques. In this dissertation, two different AM techniques for glass AM were developed, Selective Laser Melting (SLM) and filament fed process.</p> …
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High-Temperature Displacement Sensor Using a White-Light Scanning Fiber Michelson Interferometer
… available sapphire fiber possesses poor optical quality and is not available with a cladding. It has found use in a variety of temperature sensors, but the investigation of sapphire-based strain and displacement sensors has been limited. The primary development of a white-light Michelson …
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Analysis and fabrication of paraboloidal CFRP sandwich mirrors.
… balloon-borne, Cassegrain telescope required an optical quality better than 30 microns in figure RMS error. A parametric study on composite sandwich mirrors was conducted by using finite element analysis as well as optical analysis. The factors covered the cell sizes, core materials, core …
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Fundamentals of spatial vision in the barn owl (Tyto alba pratincola) : ocular aberrations, grating acuity, contrast sensitivity, and vernier acuity
Optical quality in barn owl eyes was measured with a standard Tscherning-type wavefront aberrometer. The results revealed that barn owl eyes have excellent optical quality. Higher-order aberrations were about 3-fold lower than has been reported in human eyes with similar methods and under …
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Optimisation and fabrication of ultra violet emitting CuC1 thin films by RF sputtering
… a suitable bias to the substrate and high quality stoichiometric CuCl films were obtained. Microstructural evaluation revealed that the grain interface area of the film increases on increasing the sputtering pressure. UV emission properties were found to be influenced by the existence of …
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Shadow mask assisted heteroepitaxy of compound semiconductor nanostructures
… nanostructures of high structural and optical quality. In order to accomplish this, technological processes have been developed and optimized. This, in combination with model calculations of the basic kinetic growth processes has enabled the fabrication of high quality quantum …
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Fabrication and characterization of compound semiconductor nanostructures
… and $\rm In\sb{x}Ga\sb{1-x}As/GaAs$, and the optical properties of the fabricated structures. Requirements on the electron beam lithography for each fabrication technique are presented, with emphasis on the capabilities of the lithography tool and parameters of the resist material, in …
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On the growth and characterisation of Zinc Oxide
Optical, electrical and structural properties of ZnO grown via grown via PLD and VPT were examined. Both growth techniques were successful in producing nanostructured ZnO with thin films also produced with PLD. An epitaxial relationship to the substrate was found for all materials. A …
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The growth and characterisation of ordered arrays of zinc oxide nanostructures and optical studies of defects in zinc oxide
… and a hybrid CBD / CTR-VPT method. The best optical quality nanorods were obtained by the hybrid CBD / CTR-VPT method. This hybrid method was extended further and a method was developed to deposit hexagonally close packed positioned c-axis aligned arrays using a facile nanosphere technique in …
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Design and Performance of Cold Bent Glass
… limits are exceeded and could degrade the optical quality of the glass. An evaluation procedure is also formulated to set limits and aid designers/manufacturers to predict the mechanical response and the optical quality of the glass. Cold bent glass is subjected to permanent bending …
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Fabrication of site-controlled quantum structures for optoelectronic devices
… of “regrown QDs”. In this approach, high optical quality InAs QDs are regrown in designed nucleation sites over GaAs substrate, and the effects of process and growth parameters on the structural and optical properties of regrown QDs will be examined. In contrast, “pillar QDs” are …
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Time and temperature dependence of stimulated brillouin scattering in fused silica
… principal material to be studied because of its optical and acoustic isotropy and its availability in large, optical quality samples. Also, it has the advantage of a distinct dependence of acoustic attenuation on temperature. The main difficulty in using stimulated scattering to determine phonon …
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