Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Characterization of a division-of-focal-plane polarization imager(Montana State University - Bozeman, College of Engineering, 2020) Syed, Musaddeque Anwar Al Abedin; Chairperson, Graduate Committee: Joseph A. ShawPolarization is a fundamental property of light that can be detected with polarization-sensitive instruments. Imaging polarimetry has an immensely wide range of applications, and while much has been accomplished in recent years, there is still a need for sensor systems with improved accuracy, precision, and stability. This paper presents the optical characterization of a commercial division-of-focal plane (DoFP) polarization imager, in an effort to evaluate its performance as a promising instrument in the application of ground-based cloud thermodynamic phase detection. Radiometric characterization values were well within the acceptable region, but the polarimetric contrast was in the range of 20-30, much lower than expected, which may be a result of the broadband measurements being impaired by poor polarizer performance at the blue end of the spectrum. Later, a narrowband polarimetric measurement at 532 + or - 5 nm produced a much enhanced result, with polarimetric contrast in the higher 300s, making the imager a viable option for many remote sensing applications. Also, all-sky imaging of clear daytime sky and its analysis of degree of linear polarization (DoLP) showed encouraging result.Item Combining spectral and polarimetric methods to classify cloud thermodynamic phase(Montana State University - Bozeman, College of Engineering, 2019) Tauc, Martin Jan; Chairperson, Graduate Committee: Joseph A. Shaw; David W. Riesland, Laura M. Eshelman, Wataru Nakagawa and Joseph A. Shaw were co-authors of the article, 'Radiance ratios for CTP discrimination' submitted to the journal 'Journal of applied remote sensing' which is contained within this thesis.; Wataru Nakagawa and Joseph A. Shaw were co-authors of the article, 'The SWIR three-channel polarimeter for cloud thermodynamic phase detection' in the journal 'Optical engineering' which is contained within this thesis.Cloud thermodynamic phase--whether a cloud is composed of spherical water droplets or polyhedral ice crystals--is an important parameter for optical communication with space-based instruments, remote sensing of the atmosphere, and, perhaps most importantly, understanding weather and climate. Although some methods exist to detect the phase of clouds, there is still a need for passive remote sensing of cloud thermodynamic phase due to its low-cost, scalability, and ease of use. Two methods for cloud thermodynamic phase classification employ spectral radiance ratios in the short-wave infrared, and the S 1 Stokes parameter, a polarimetric quantity. In this dissertation, the combination of the two methods is realized in an instrument called the short-wave infrared three-channel polarimeter. The coalescence of radiance ratios in the short-wave infrared and polarization channels oriented parallel and perpendicular to the scattering plane provides better classification of cloud phase than either method independently. Despite the improvement, the low-cost system suffered from hardware and software limitations, which caused an increase in noise and polarimetric artifacts. These errors are analyzed and a subset of low-noise data shows even better classification ability. All together, the results attained from the deployment of the polarimeter in early 2019 showed promise that the combination of the two methods is an improvement over past techniques.Item Weed and crop discrimination with hyperspectral imaging and machine learning(Montana State University - Bozeman, College of Engineering, 2019) Scherrer, Bryan Joseph; Chairperson, Graduate Committee: Joseph A. ShawHerbicide-resistant weed biotypes are spreading across crop fields nationally and internationally and mapping them with traditional crop science methods - cloning plants and testing their resistance levels in a lab - are costly and time consuming. A segment of the field of precision agriculture is being developed to accurately and quickly map the location of herbicide-resistant and herbicide-susceptible weeds using advanced optics and computer algorithms. In our study, we collected hundreds of thousands of spectra of herbicide-resistant and herbicide-susceptible biotypes of the weeds kochia, mare's tail and lamb's quarter and of crops including barley, corn, dry pea, garbanzo, lentils, pinto bean, safflower, sugar beet at the Southern Agricultural Research Center in Huntley, Montana using a hyperspectral imager. Plants were imaged in a controlled greenhouse setting as well as in crop fields using ground-based and drone-based imaging platforms. The spectra were differentiated from one another using a feedforward neural network machine learning algorithm. Classification accuracies depended on what plants were imaged, the age of the plants and lighting conditions of the experiment. They ranged from 77% to 99% for spectra acquired on our ground-based imaging platform and from 25% to 79% on our drone- based platform.Item A study of atmospheric polarization in unique scattering conditions at twilight, during a solar eclipse, and for cloud phase retrievals using all-sky polarization imaging(Montana State University - Bozeman, College of Engineering, 2018) Eschelman, Laura Marie; Chairperson, Graduate Committee: Joseph A. ShawPolarization is a fundamental property of light that can be detected with polarization-sensitive instruments for many remote sensing applications. To quantitatively interpret the remote sensing data, an understanding how naturally occurring polarization depends on wavelength and environmental parameters is needed. The most obvious source of naturally occurring polarization is atmospheric scattering. For a clear-sky environment, Rayleigh scattering dominates, resulting from scattering by atmospheric gas molecules that are much smaller than the optical wavelength, and a distinct all-sky polarization pattern exists. A band of maximum degree of linear polarization can be observed 90? from the sun with polarization vectors orientated perpendicular to the scattering plane (i.e. the plane containing the incident and scattered light). However, aerosols, clouds, and underlying surface reflectance can alter the observed sky polarization. Military, environmental, and navigational applications exploit the sky polarization pattern to detect objects, retrieve aerosol and cloud properties, and to find compass headings based on the sky polarization pattern. Sky polarization is also being used to calibrate the polarization response of large telescopes. It is important to understand how partially polarized skylight can vary with environmental factors, as well as with wavelength and solar position, so that polarization measurements can be interpreted correctly. The direction of polarization when aligned to a specific reference frame can provide additional information beyond the basic polarization pattern. This dissertation expands the current knowledge of skylight polarization by validating radiative transfer simulations in the shortwave infrared, by reporting the first-ever retrievals of cloud thermodynamic phase from all-sky polarization images using the Stokes S1 parameter referenced in the scattering plane, and by quantifying how partially polarized skylight varied under unique scattering conditions during the 2017 solar eclipse. In order to accurately predict cloud thermodynamic phase and to analyze the temporal distribution of skylight during a total solar eclipse, a physics-based understanding of the Stokes parameters and angle of polarization (AoP) with respect to the instrument, scattering, and solar principal planes was also developed. Through each experiment, two underlying threads were observed. First, in order to accurately interpret results, environmental parameters needed to be characterized. Second, when rotated into a specific reference frame, the Stokes parameters and AoP can be utilized differently and provide unique insights when analyzing all-sky polarization data.Item Ultra high-throughput fluorescence detection for single cell applications in drop microfluidics(Montana State University - Bozeman, College of Engineering, 2016) Schaefer, Robert Willman; Chairperson, Graduate Committee: Connie ChangConventional methods in microbiology can be limited by assay execution and analysis times, phenotypic dominance within bulk communities, reagent volumes, and single-use supply costs. These limitations can be overcome using drop-based microfluidics. In this discipline, pico-liter sized, water-in-oil emulsions serve as independent 'test tubes,' allowing for the compartmentalization of community constituents and interrogation at the single cell level. Furthermore, two-phase, continuous flow microfluidic devices enable drop populations to be manipulated and analyzed at kilohertz rates according to experimental needs. In this research, a fluorescence-based method for drop analysis and sorting was developed and applied, in conjunction with other microfluidic techniques, to perform assays in microbiology. The applications explored include cell dormancy within P. aeruginosa subpopulations, microalgae lipid accumulation for the production of biofuels, optimization of microbially-induced calcite precipitation (MICP), and human norovirus infectivity. Results from each application include: 1. The hibernation promoting factor (Hpf) was found to play a key role in the maintenance of P. aeruginosa viability during planktonic starvation. 2. Progress was made on a Nile Red based, ultra high-throughput, single cell algal lipid detection platform. 3. MICP was demonstrated at the single cell level. 4. A drop based human norovirus infection platform was attempted using human B cells as the viral host.Item Infrared cloud imaging systems characterization(Montana State University - Bozeman, College of Engineering, 2016) Riesland, David Walter; Chairperson, Graduate Committee: Joseph A. ShawInfrared cloud imaging (ICI) is a useful tool for characterizing cloud cover for a variety of fields. Clouds play an important role in free-space high frequency (optical and mm-wave) terrestrial communications. Ground-based infrared imagers are used to provide long-term, high resolution (spatial and temporal) cloud data without the need for sunlight. This thesis describes the development and characterization of two ICI systems for deployment at remote field sites in support of Earth-to-space mm-wave and optical communication experiments. The hardware upgrades, calibration process, sensitivity analysis, system validation, and algorithm developments are all discussed for these systems. Relative spectral response sensitivity analysis is discussed in detail, showing as much as 35% calibrated scene radiance uncertainties when using generic manufacturer data in comparison with measured spectral responses. Cloud discrimination algorithms, as well as cloud phase (ice or water discrimination) algorithms are also discussed.Item Silicon nitride deformable mirrors for focus and spherical aberration correction in micro-optical systems(Montana State University - Bozeman, College of Engineering, 2002) Himmer, Phillip Alexander; Chairperson, Graduate Committee: David Dickensheets.Laser beam scanning systems benefit from dynamic focus control and aberration correction using a deformable mirror, enabling 3D real-time scanning. Designed for focus and spherical aberration control in optical beam scanning systems, these mirrors are capable of video rate bandwidths allowing real-time 3D imaging in micro-optical scanning systems. Field curvature aberration can also be corrected with the same mirror. Previous work with polysilicon deformable mirrors validated the concept of using specialized deformable optics in beam scanning systems. Fabrication of micro-optics in this dissertation was achieved using a modified surface micromachining technique with silicon nitride replacing polysilicon as the structural material. A bulk anisotropic silicon etch following a PSG release etch allows the creation of a variable cavity depth, overcoming the typical deformation limitations of standard surface micromachining. To perform as desired, parabolic curvature of the mirror surface is required with the ability to introduce positive and negative quartic curvature. Analytical theory showed that deformed simply supported plates have curvature closer to parabolic than deformed clamped plates. Segmentation and thinning of the perimeter was done to in order to emulate this simply supported boundary. Two annular actuation zones were implemented to give independent control over the second and fourth order curvatures. It was found that residual stress present in the silicon nitride structural plate improved the surface curvature and mechanical resonance at the expense of a larger actuation pressure. Mirrors with diameters of 1500, 1000, 750, and 300 microns were built and tested. Zonal actuation with annular electrodes proved successful in providing sufficient correction of the mirror surface curvature, allowing spherical aberration free focus control. Perimeter segmentation greatly reduced required actuation loads allowing improved focal ranges. It was found that the sacrificial layer thickness has a significant impact on the initial curvature of the mirror. Sacrificial layers 0.2 microns thick proved sufficient for release, improved device yield, and resulted in an initially flat mirror.Item Investigation of physically aware routing and wavelength assignment (RWA) algorithms for next generation transparent optical networks(Montana State University - Bozeman, College of Engineering, 2010) Hahn, Timothy Allen; Chairperson, Graduate Committee: Brendan MumeyOptical networks form the foundation of today's information infrastructure. Current generation optical networks consist largely of point-to-point electronically transmitted links which switch between nodes and repeaters. There is a trend in optical networking to move from the current generation opaque networks toward transparent networks. Transparent networks use only optical devices, eliminating the costly need for OEO conversions. Unfortunately, transparent networks present a unique challenge in maintaining acceptable signal quality levels. This research is an investigation of RWA algorithms in transparent optical networks. We present RAPTOR, a custom built discrete event program to simulate optical networks. RAPTOR uses its physically aware modules to accurately calculate three of the dominant physical impairments. RAPTOR is fast and multi-threaded. We introduce several new performance metrics. RAPTOR enables us to study transparent optical networks in a unique and realistic manner. We conduct an extensive performance analysis of existing RWA algorithms. We explore many different traffic models, traffic loads, signal quality, and network topologies in a comprehensive fashion. We directly compare the leading RWA algorithms in a manner has not been done before. We studied new RWA algorithms in two fields: Dynamic Programming and Ant Colony Optimization. Our new Dynamic Programming based algorithm has the best overall performance in most scenarios. It is flexible and adapts well to all network conditions we studied. It shows good promise for future optical networks.Item Carbon dioxide sequestration underground laser based detection system(Montana State University - Bozeman, College of Engineering, 2009) Barr, Jamie Lynn; Chairperson, Graduate Committee: Kevin S. Repasky; John L. Carlsten (co-chair)Carbon dioxide (CO 2) is a known greenhouse gas. Due to the burning of fossil fuels by industrial and power plants the atmospheric concentration of CO 2 has been rising over the past 50 years. Carbon capture and sequestration provides a method to prevent CO 2 from being emitted into the atmosphere. Successful carbon sequestration will require the development of many pieces of technology including development of monitoring tools and techniques. An underground laser based monitoring system was built and tested at Montana State University (MSU) to measure sub-surface CO 2 concentrations at a sequestration site. The instrument uses differential absorption spectroscopy by temperature tuning a distributed feedback diode laser over several CO 2 absorption features located at 2.004 microns. The instrument utilizes photonic bandgap fibers for sub-surface spectroscopy CO 2 concentration measurements. The instrument was tested at a controlled release facility located on the MSU campus. The field and CO 2 release are managed by the Zero Emissions Research and Technology group at MSU. Three CO 2 injection tests were done over the coarse of two summers to simulate a fault or fracture line at a sequestration site. Results from all three tests are presented showing that the underground differential absorption instrument could be used to monitor sequestration sites.Item Anti-stokes generation in a continuous-wave raman laser(Montana State University - Bozeman, College of Letters & Science, 2008) Murphy, Sytil Kathleen; Chairperson, Graduate Committee: John L. CarlstenThe continuous-wave Raman laser system differs from other Raman systems in that it uses cavity enhancement to augment the pump laser source rather than a high-power pulsed laser source. Through interactions of the pump laser with the Raman active medium, all Raman systems can produce both red-shifted, Stokes, emission and blue-shifted, anti-Stokes, emission. Previous, continuous-wave Raman laser systems have focused on the Stokes emission. This dissertation presents theory and data on the anti-Stokes emission. Specifically, it investigates the anti-Stokes mode structure and the emitted power as a function of input pump power, detuning, pressure, and mode combination. In order to be able to compare theory to data, the existing semi-classical CW Raman laser theory is extended to include the possibility that the spatial mode of any of the three fields (pump, Stokes, or anti-Stokes) is not the fundamental spatial mode. Numerical simulations of this theory are used to understand the behavior of the CW Raman system. All the data is compared to the theory, with varying degrees of success. The pump laser used in this research is a frequency-doubled Nd:YAG at 532 nm and the Raman active medium is H 2. This combination results in Stokes and anti- Stokes wavelengths of 683 nm and 435 nm, respectively. Five methods were found in this research for increasing the amount of anti-Stokes emitted: increasing the input pump power, detuning from gain line-center of the Stokes emission, increasing the reflectivity of the cavity mirrors at the anti-Stokes wavelength, switching to a higher-order spatial mode, and decreasing the H 2 pressure within the Raman cavity. In general, it was found that the higher-order anti-Stokes modes did not agree with a single theoretical spatial mode. Superpositions were formed of multiple theoretical spatial modes giving intensity distribution across the profile similar to the measured profile. Three theoretical spatial mode symmetries were investigated: rectangular, cylindrical, and elliptical. Also measured was the Raman gain as a function of pressure. The accepted theory for the Raman linewidth was found to be slightly off.