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Full-Text Articles in Physics
Periodic Trends In The Infrared And Optical Absorption Spectra Of Metal Chalcogenide Clusters, Alain Ward
Periodic Trends In The Infrared And Optical Absorption Spectra Of Metal Chalcogenide Clusters, Alain Ward
Theses and Dissertations
We have investigated the Optical absorption, Infrared spectra, Binding Energies, and various other cluster properties to determine the existence of periodic trend for Transition Metal Chalcogenide Clusters ligated with CO ligands. We were motivated to answer the question of whether periodic behavior can be observed in properties of octahedral metal-chalcogenide clusters. We have used the Amsterdam Density Functional code to calculate the electronic structure of Transition Metal Chalcogenide Clusters using gradient-corrected density functional theory. We determined the existence of several periodic trends in properties of octahedral Transition Metal Chalcogenide Clusters TM6Se8(CO)6. To investigate these …
Characterization Of Infrared Metasurface Optics With An Optical Scatterometer, Matthew R. Miller
Characterization Of Infrared Metasurface Optics With An Optical Scatterometer, Matthew R. Miller
Theses and Dissertations
An optical scatterometer is used to characterize the infrared scatter of a dielectric metasurface cylindrical lens and two variants of that design. The design uses dielectric nanopillars to create the parabolic phase delay required for lensing; the variants change the length of the nanopillars from the design length of 4 microns to 0.9 and 5.2 microns. Scatter measurements were made at the design wavelength of 4 microns, and at 3.39 and 5 microns. These measurements showed wide-angle scatter greater than that measured for a conventional refractive optic, and that these metasurfaces perform their optical function best at the design wavelength …
Scattering In Infrared Microspectroscopy, Alex James Schofield
Scattering In Infrared Microspectroscopy, Alex James Schofield
Theses and Dissertations
Mid-infrared absorbance spectra obtained from spatially inhomogeneous and finite samples often contain scattering effects that undermine the Beer-Lambert law assumption. Such spectra contain generally non-linear contributions from the scattering material’s complex refractive index, which may result in derivative-like bands with shifted peak positions. It is first shown using Mie theory for spherical scatterers, that these band distortions may be interpreted and accurately modeled by Fano theory when the imaginary part of its complex dielectric function is small and Lorentzian in nature—as is the case for many biological media. By fitting Fano line shapes to isolated absorbance bands, recovery of the …
Infrared And Electro-Optical Stereo Vision For Automated Aerial Refueling, William E. Dallmann
Infrared And Electro-Optical Stereo Vision For Automated Aerial Refueling, William E. Dallmann
Theses and Dissertations
Currently, Unmanned Aerial Vehicles are unsafe to refuel in-flight due to the communication latency between the UAVs ground operator and the UAV. Providing UAVs with an in-flight refueling capability would improve their functionality by extending their flight duration and increasing their flight payload. Our solution to this problem is Automated Aerial Refueling (AAR) using stereo vision from stereo electro-optical and infrared cameras on a refueling tanker. To simulate a refueling scenario, we use ground vehicles to simulate a pseudo tanker and pseudo receiver UAV. Imagery of the receiver is collected by the cameras on the tanker and processed by a …
Plasmonic Grating Geometrics And Wavelength-Dependent Focus Depth In Infrared Detectors, Patrick R. Kennedy
Plasmonic Grating Geometrics And Wavelength-Dependent Focus Depth In Infrared Detectors, Patrick R. Kennedy
Theses and Dissertations
The objective for this research is to determine a relationship between plasmonic grating geometries and the wavelength-dependent focus depth. This research is focused on enhancing the signal collected by infrared detectors by using a metal grating as a planar lens to focus light in the detecting region of the substrate. This can be used to maintain a thinner absorbing region and possibly to create multi-color imaging in a single pixel. Simulations demonstrate that the plasmonic lens is capable of creating a wavelength dependent focus spot.
Biomedical Applications Of Mid-Infrared Spectroscopic Imaging And Multivariate Data Analysis: Contribution To The Understanding Of Diabetes Pathogenesis, Ebrahim Aboualizadeh
Biomedical Applications Of Mid-Infrared Spectroscopic Imaging And Multivariate Data Analysis: Contribution To The Understanding Of Diabetes Pathogenesis, Ebrahim Aboualizadeh
Theses and Dissertations
Diabetic retinopathy (DR) is a microvascular complication of diabetes and a leading cause of adult vision loss. Although a great deal of progress has been made in ophthalmological examinations and clinical approaches to detect the signs of retinopathy in patients with diabetes, there still remain outstanding questions regarding the molecular and biochemical changes involved. To discover the biochemical mechanisms underlying the development and progression of changes in the retina as a result of diabetes, a more comprehensive understanding of the bio-molecular processes, in individual retinal cells subjected to hyperglycemia, is required. Animal models provide a suitable resource for temporal detection …
Total Electron Count Variability And Stratospheric Ozone Effects On Solar Backscatter And Lwir Emissions, John S. Ross
Total Electron Count Variability And Stratospheric Ozone Effects On Solar Backscatter And Lwir Emissions, John S. Ross
Theses and Dissertations
The development of an accurate ionospheric Total Electron Content (TEC) model is of critical importance to High Frequency (HF) radio wave propagation. However, the TEC is highly variable and is continuously influenced by geomagnetic storms, extreme Ultraviolet (UV) radiation, diurnal variation, and planetary waves. The ability to capture this variability is essential to improve current TEC models. Analysis of the growing body of data involving ionospheric fluctuations and thermal tides has revealed persistent correlation between increases in stratospheric ozone and variability of the TEC. The spectral properties of ozone show that it is a greenhouse gas that alters longwave emissions …
Probing Bonding And Dynamics At Heterogeneous Adsorbate/Graphene Interfaces, Eric Charles Mattson
Probing Bonding And Dynamics At Heterogeneous Adsorbate/Graphene Interfaces, Eric Charles Mattson
Theses and Dissertations
Graphene-based materials are becoming an astoundingly promising choice for many relevant technological and environmental applications. Deriving graphene from the reduction of graphene oxide (GO) is becoming a popular and inexpensive route toward the synthesis of these materials. While the desired product from GO reduction is pristine graphene, defects and residual oxygen functional groups inherited from the parent GO render reduced graphene oxide (RGO) distinct from graphene. In this work, the structure and bonding for GO and RGO is investigated to the end of a working understanding of the composition and properties of these materials. In situ selected area electron diffraction …
Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell
Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell
Theses and Dissertations
The spectral and spatial radiative properties of coherent thermal emission in the mid- and far-IR through the use of micro and nano-structured metal-semiconductor materials were designed and demonstrated experimentally. Using an implementation of the Rigorous Coupled Wave Analysis and Computer Simulation Technology (CST), two structures were designed to selectively emit at mid- and far-IR wavelengths, a 1-D truncated multilayer resonator and a 3-D hybrid photonic crystal (PC)-multilayer. A High Impulse Power Magnetron Sputtering (HIPIMS) deposition technique was used to fabricate two silver-germanium-silver (Ag-Ge-Ag) resonating structures with layer thicknesses of 6-240-160 nm for one sample and 6-700-200 nm for the other. …