Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (295)
- Electrical and Computer Engineering (293)
- Electromagnetics and Photonics (291)
- Atomic, Molecular and Optical Physics (4)
- Chemistry (4)
-
- Life Sciences (3)
- Plasma and Beam Physics (3)
- Analytical Chemistry (2)
- Analytical, Diagnostic and Therapeutic Techniques and Equipment (2)
- Biochemistry (2)
- Biochemistry, Biophysics, and Structural Biology (2)
- Biomedical Engineering and Bioengineering (2)
- Medicine and Health Sciences (2)
- Physical Chemistry (2)
- Applied Mathematics (1)
- Bioimaging and Biomedical Optics (1)
- Bioinformatics (1)
- Biological and Chemical Physics (1)
- Biophysics (1)
- Botany (1)
- Cancer Biology (1)
- Cell Biology (1)
- Cell and Developmental Biology (1)
- Communication (1)
- Education (1)
- Engineering Physics (1)
- Genetics and Genomics (1)
- Keyword
-
- Nonlinear optics (17)
- Optics (15)
- Liquid crystal (10)
- Laser (9)
- Semiconductor lasers (7)
-
- Photonics (6)
- Coherence (5)
- Diffraction (5)
- Lasers (5)
- Solitons (5)
- Femtosecond (4)
- Fiber laser (4)
- Infrared (4)
- Liquid crystals (4)
- Polarization (4)
- Random media (4)
- Scattering (4)
- Semiconductor laser (4)
- Semiconductors (4)
- Spectroscopy (4)
- Adaptive lens (3)
- Beam shaping (3)
- Blue phase (3)
- Blue phase liquid crystal (3)
- Chalcogenide (3)
- Coherent Detection (3)
- Display (3)
- Erbium (3)
- Frequency combs (3)
- Holography (3)
- Publication Year
- Publication
- Publication Type
Articles 31 - 60 of 352
Full-Text Articles in Optics
Compact Lens Technologies: Curved Image Sensor And Volumetric Imaging Efficiency, Zhao Ma
Compact Lens Technologies: Curved Image Sensor And Volumetric Imaging Efficiency, Zhao Ma
Electronic Theses and Dissertations, 2020-2023
Compact image systems bring up people's attention in the field of target recognition, surveillance, situation awareness or even photography. Conventional metrics assess image system based on image quality without considering systems' volume. More comprehensive metrics, such as General Image-Quality Equation and the Targeting Task Performance metric, incorporates all image system components from object, lenses to detector and even imaging processing algorithm. All these key factors prohibit these metrics from being applied to image system in a convenient manner. Here, we propose a simple metric, volumetric imaging efficiency, considering both image quality and volume. Only concentrate on optical lenses enables the …
Third Order Nonlinear Optics In Solids, Nicholas Cox
Third Order Nonlinear Optics In Solids, Nicholas Cox
Electronic Theses and Dissertations, 2020-2023
Nonlinear optical effects occur when strong electromagnetic waves induce changes in a medium that affect its own propagation or that of another wave. Third order optical nonlinearities scale linearly with irradiance and lead to effects like two-photon absorption and nonlinear refraction. This work focuses on the experimental and theoretical study of two-photon absorption in crystalline solids. We begin by detailing the quantum mechanical states of electrons in solids along with the computational approaches to calculate their band structure. Next, a theoretical model for the linear and nonlinear optical interaction of light with matter is presented in a many-body formalism. This …
Optimization-Based Approaches To Low-Coherence Optical Diffraction Tomography, Seth Smith-Dryden
Optimization-Based Approaches To Low-Coherence Optical Diffraction Tomography, Seth Smith-Dryden
Electronic Theses and Dissertations, 2020-2023
Quantitative optical phase imaging techniques, such as optical diffraction tomography (ODT), are useful tools for refractive-index profiling. Many of them, however, rely on the weak-scattering assumptions, thus cannot be applied to multiple-scattering objects, or turbid media. In this thesis, I report several approaches for expanding the efficacy of ODT techniques and adapting them to new applications by use of low-coherence broadband illumination. First, I developed a method for ODT reconstruction using regularized convex optimization with a new phase-based fidelity criterion. The new criterion is necessary because objects with very different refractive-index distributions may produce similar diffracted fields (magnitude and principal-phase) …
Light Trapping Transparent Electrodes, Mengdi Sun
Light Trapping Transparent Electrodes, Mengdi Sun
Electronic Theses and Dissertations, 2020-2023
Transparent electrodes represent a critical component in a wide range of optoelectronic devices such as high-speed photodetectors and solar cells. Fundamentally, the presence of any conductive structures in the optical path leads to dissipation and reflection, which adversely affects device performance. Many different approaches have been attempted to minimize such shadowing losses, including the use of transparent conductive oxides (TCOs), metallic nanowire mesh grids, graphene-based contacts, and high-aspect ratio metallic wire arrays. In this dissertation I discuss a conceptually different approach to achieve transparent electrodes, which involves recapturing photons initially reflected by highly conductive electrode lines. To achieve this, light-redirecting …
Spectral Dependence Of Deep Subwavelength Metallic Apertures In The Mid-Wave Infrared, Heath Gemar
Spectral Dependence Of Deep Subwavelength Metallic Apertures In The Mid-Wave Infrared, Heath Gemar
Electronic Theses and Dissertations, 2020-2023
For two decades, extraordinary optical transmission (EOT) has amplified exploration into subwavelength systems. Researchers have previously suggested exploiting the spectrally selective electromagnetic field confinement of subwavelength cavities for multispectral detectors. Utilizing the finite-difference frequency domain (FDFD) method, we examine electromagnetic field confinement in both 2-dimensional and 3-dimensional scenarios from 2.5 to 6 microns (i.e., mid-wave infrared or MWIR). We explore the trade space of deep subwavelength cavities and its impact on resonant enhancement of the electromagnetic field. The studies provide fundamental understanding of the coupling mechanisms allowing for prediction of resonant spectral behavior based on cavity geometry and material properties. …
High Spectral Brightness, Broad Area Quantum Cascade Lasers, Enrique Sanchez Cristobal
High Spectral Brightness, Broad Area Quantum Cascade Lasers, Enrique Sanchez Cristobal
Electronic Theses and Dissertations, 2020-2023
Quantum cascade lasers are unipolar semiconductor lasers that offer a unique combination of compact size, high efficiency, high optical power, and flexibility to achieve a targeted emission wavelength with the same laser core material composition, employing so-called bandgap engineering. Since their invention in 1994, watt-level CW power with 5 to 20 % wallplug efficiency was demonstrated for QCLs throughout the entire 4 to 12 µm range, which makes QCLs very attractive for a number of practical applications. Our earlier work on broad-area QCLs emitting in the 4.6 µm to 5.7 µm spectral range demonstrated that CW power scaling with lateral …
Nonlinear Light-Matter Interactions In Novel Crystals For Broadband Mid-Infrared Generation, Taiki Kawamori
Nonlinear Light-Matter Interactions In Novel Crystals For Broadband Mid-Infrared Generation, Taiki Kawamori
Electronic Theses and Dissertations, 2020-2023
Mid-infrared (MIR) laser sources have demonstrated diverse applications in science and technology. For spectroscopy applications, numerous molecules have unique absorption features in this range, and one needs a spectrally broad coherent laser source for parallel detection of mixtures of species. Frequency down-conversion in nonlinear optical materials via second-order nonlinear susceptibility is one of the promising techniques to generate the spectral coverage of more than an octave in the MIR, assisted by emerging novel crystals. The nonlinear light-matter interactions in such special crystals as ZnSe ceramics have not been analyzed. Additionally, through the use of high-intensity few-cycle optical pulses, high-order nonlinear …
The Physics Of Nanoaperture Optical Traps: Design, Fabrication And Experimentation, Chenyi Zhang
The Physics Of Nanoaperture Optical Traps: Design, Fabrication And Experimentation, Chenyi Zhang
Electronic Theses and Dissertations, 2020-2023
Recent progress in nano optics, spurred by progress in nanofabrication, has allowed us to overcome these challenges. We use surface plasmon polaritons to break the optical diffraction limit and squeeze the photon energy into a local hot spot. The small mode volume of a plasmonic antenna or nanoaperature significantly enhances the local field and can be designed to resonate at a desired wavelength. By designing, fabricating, and testing these nanoapertures, I trap single nanoparticles with significantly reduced laser power by measuring the monochromatic transmission change of a resonant aperture. A freely diffused nanoparticle, behaving like a dipole antenna, interacts with …
Novel Optical Frequency Combs Injection Locking Architectures, Ricardo Bustos Ramirez
Novel Optical Frequency Combs Injection Locking Architectures, Ricardo Bustos Ramirez
Electronic Theses and Dissertations, 2020-2023
Due to their highly stable timing characteristics, optical frequency combs have become instrumental in applications ranging from spectroscopy to ultra-wideband optical interconnects, high-speed signal processing, and exoplanet search. In the past few years, there has been a necessity for frequency combs to become more compact, robust to environmental disturbances, and extremely energy efficient, where photonic integration shows a clear pathway to bring optical frequency combs to satellites, airships, drones, cars, and even smartphones. Therefore, the development of chip-scale optical frequency combs has become a topic of high interest in the optics community. This dissertation reviews the work made in the …
Analysis And Design Of Infrared Fiber Bundles For Large Field-Of-View Thermal Imaging, Cesar A. Lopez-Zelaya
Analysis And Design Of Infrared Fiber Bundles For Large Field-Of-View Thermal Imaging, Cesar A. Lopez-Zelaya
Honors Undergraduate Theses
During the DARPA SCENICC program, J. Ford, et al., demonstrated that CFBs provide a compelling route to compact, wide angle imagers. Monocentric lenses readily provide diffraction-limited images over wide field but onto a hemispherically curved image surface. They demonstrated visible CFBs can be tapered, cut and polished to relay curved images to flat sensors. We have shown that this provides a volumetric imaging efficiency a hundredfold larger than bulk optics can produce; a hundred times the resolution in the same volume or a hundred times less volume for the same resolution. Ford's work leveraged commercial fiber bundles available for the …
Liquid Crystal Flat Optics For Near-Eye Displays, Tao Zhan
Liquid Crystal Flat Optics For Near-Eye Displays, Tao Zhan
Electronic Theses and Dissertations, 2020-2023
Augmented reality (AR) and virtual reality (VR) displays, considered as the next-generation information platform, have shown great potential to revolutionize the way how we interact with each other and the digital world. Both AR and VR are disruptive technologies that can enable numerous applications in education, healthcare, design, training, entertainment, and engineering. Among all the building blocks of these emerging devices, near-eye displays (NEDs) play a critical role in the entire system, through which we can perceive the virtual world as the real one. However, the visual experience offered by existing NED technologies is still far from satisfying the human …
Measurement And Mitigation Of Optical, Recombination And Resistive Losses In Silicon Photovoltaics, Mohammad Jobayer Hossain
Measurement And Mitigation Of Optical, Recombination And Resistive Losses In Silicon Photovoltaics, Mohammad Jobayer Hossain
Electronic Theses and Dissertations, 2020-2023
Today, most of the photovoltaic cells in the market are made of silicon. Great achievements are being attained every year in terms of reducing the price of this kind of cells and improving their efficiency, reliability and durability. However, further improving the cell performance is a challenging task because of the presence of optical, recombination and resistive loss mechanisms in the cell. This work is focused on the measurement and mitigation of these losses. Mitigation of the optical, recombination and resistive losses at first require quantifying those losses and their impacts on the cell performance metrics accurately. Traditionally, solar cells …
On The Information Content In Unresolved Imaging, Zhean Shen
On The Information Content In Unresolved Imaging, Zhean Shen
Electronic Theses and Dissertations, 2020-2023
Imaging is almost synonymous with optics. Imaging is the process of using light to form a tangible or visible representation, an imitation (imitari) of a material property. There are many situations, however, where one can only aspire to 'sense making' rather than forming an image per se. In other words, objects cannot be directly resolved by conventional intensity-based imaging, a situation commonly referred to as 'unresolved imaging'. However, there is still information retained in other properties of light, which can be exposed by other means. In this thesis I will discuss two typical situations: subwavelength and multiple scattering, which are …
Multi-Functional Fluorescence Microscopy Via Psf Engineering For High-Throughput Super-Resolution Imaging, Jinhan Ren
Multi-Functional Fluorescence Microscopy Via Psf Engineering For High-Throughput Super-Resolution Imaging, Jinhan Ren
Electronic Theses and Dissertations, 2020-2023
Image-based single cell analysis is essential to study gene expression levels and subcellular functions with preserving the native spatial locations of biomolecules. However, its low throughput has prevented its wide use to fundamental biology and biomedical applications which require large cellular populations in a rapid and efficient fashion. Here, we report a 2.5D microcopy (2.5DM) that significantly improves the image acquisition rate while maintaining high-resolution and single molecule sensitivity. Unlike serial z-scanning in conventional approaches, volumetric information is simultaneously projected onto a 2D image plane in a single shot by engineering the fluorescence light using a novel phase pattern. The …
Development Of Quantitative Intensity-Based Single-Molecule Assays, Benjamin Croop
Development Of Quantitative Intensity-Based Single-Molecule Assays, Benjamin Croop
Electronic Theses and Dissertations, 2020-2023
Fluorescence microscopy has emerged as a popular and powerful tool within biology research, owing to its exceptional signal contrast, specificity, and the versatility of the various microscope designs. Fluorescence microscopy has been used to study samples across orders of magnitude in physical scale ranging from tissues to cells, down to single-molecules, and as such has led to breakthroughs and new knowledge in a wide variety of research areas. In particular, single-molecule techniques are somewhat unique in their ability to study biomolecules in their native state, which enables the visualization of short-lived interactions and rare events which can be highly relevant …
High Speed Modulation Characteristics Of Semiconductor Nanolasers And Coupled Ring Laser Systems, Chi Xu
High Speed Modulation Characteristics Of Semiconductor Nanolasers And Coupled Ring Laser Systems, Chi Xu
Electronic Theses and Dissertations, 2020-2023
Optical communication systems require light sources that can be modulated with high speeds. However, the modulation bandwidth of laser diodes is typically limited by an intrinsic value, its relaxation resonance frequency. In order to circumvent this limitation, a number of methods have been proposed to boost the modulation speed, including optical injection locking, quantum dots lasers with large differential gain, push-pull modulation in composite lasers. This dissertation explores two new approaches for enhancing the direct modulation bandwidth of semiconductor quantum well laser diodes. Lasers with strong spontaneous emission have been shown to exhibit a high-speed performance theoretically. It is expected …
Directional Link Management Using In-Band Full-Duplex Free Space Optical Transceivers For Aerial Nodes, A F M Saniul Haq
Directional Link Management Using In-Band Full-Duplex Free Space Optical Transceivers For Aerial Nodes, A F M Saniul Haq
Electronic Theses and Dissertations, 2020-2023
Free-space optical (FSO) communication has become very popular for wireless applications to complement and, in some cases, replace legacy radio-frequency for advantages like unlicensed band, spatial reuse, and enhanced security. Even though FSO can achieve very high bit-rate (tens of Gbps), range limitation due to high attenuation and weather dependency has always restricted its practical implementation to indoor application like data centers and outdoor application like Project Loon. Building-to-building communication, smart cars, and airborne drones are potential futuristic wireless communication sectors for mobile ad-hoc FSO networking. Increasing social media usage demands high-speed mobile connectivity for applications like video call and …
Thermodynamic Theory Of Heavily Multimoded Nonlinear Optical Systems, Fan Wu
Thermodynamic Theory Of Heavily Multimoded Nonlinear Optical Systems, Fan Wu
Electronic Theses and Dissertations, 2020-2023
The quest for ever higher information capacities has brought about a renaissance in multimode optical waveguide systems. This resurgence of interest has recently initiated a flurry of activities in nonlinear multimode fiber optics. The sheer complexity emerging from the presence of a multitude of nonlinearly interacting modes has led not only to new opportunities in observing a host of novel optical effects that are otherwise impossible in single-mode settings, but also to new theoretical challenges in understanding their collective dynamics. In this dissertation, we present a consistent thermodynamical framework capable of describing in a universal fashion the exceedingly intricate behavior …
High Performance Micro-Scale Light Emitting Diode Display, Fangwang Gou
High Performance Micro-Scale Light Emitting Diode Display, Fangwang Gou
Electronic Theses and Dissertations, 2020-2023
Micro-scale light emitting diode (micro-LED) is a potentially disruptive display technology because of its outstanding features such as high dynamic range, good sunlight readability, long lifetime, low power consumption, and wide color gamut. To achieve full-color displays, three approaches are commonly used: 1) to assemble individual RGB micro-LED pixels from semiconductor wafers to the same driving backplane through pick-and-place approach, which is referred to as mass transfer process; 2) to utilize monochromatic blue micro-LED with a color conversion film to obtain a white source first, and then employ color filters to form RGB pixels, and 3) to use blue or …
Novel Fibers And Components For Space Division Multiplexing Technologies, Juan Carlos Alvarado Zacarias
Novel Fibers And Components For Space Division Multiplexing Technologies, Juan Carlos Alvarado Zacarias
Electronic Theses and Dissertations, 2020-2023
Passive devices and amplifiers for space division multiplexing are key components for future deployment of this technology and for the development of new applications exploring the spatial diversity of light. Some important devices include photonic lantern (PL) mode multiplexers supporting several modes, fan-in/fan-out (FIFO) devices for multicore fibers (MCFs), and multimode amplifiers capable of amplifying several modes with low differential modal gain penalty. All these components are required to overcome the capacity limit of single mode fiber (SMF) communication systems, driven by the growing data capacity demand. In this dissertation I propose and develop different passive components and amplifiers for …
Wave-Optics Simulation Of Correlated Speckle Fields, Derek Burrell
Wave-Optics Simulation Of Correlated Speckle Fields, Derek Burrell
Electronic Theses and Dissertations, 2020-2023
Laser speckle poses an ongoing challenge to optical systems that utilize coherent light for active illumination, including applications in holography, free-space communications, remote sensing and target tracking. Speckle averaging offers one potential path forward by reducing the contrast, thereby boosting signal-to-noise ratios. This approach becomes limited, however, by the degree of correlation between successive frames. Wave-optics simulations help to characterize performance gains through speckle averaging, and so it is important that existing models properly account for decorrelation rates of dynamic speckle. With that goal in mind, this research seeks to build a suite of computational wave-optics experiments that verify speckle …
Transient Mid-Ir Nonlinear Refraction In Air And Nonlinear Optical Properties Of Organometallic Complexes, Salimeh Tofighi
Transient Mid-Ir Nonlinear Refraction In Air And Nonlinear Optical Properties Of Organometallic Complexes, Salimeh Tofighi
Electronic Theses and Dissertations, 2020-2023
This dissertation explores two main topics: Transient nonlinear refraction of air in Mid-IR spectral range and nonlinear optical properties of organometallic complexes. For seeing a vibrational and rotational Raman response the molecule should be Raman active. The first requirement for being a Raman active molecule is that the polarizability of molecule must be anisotropic. Linear symmetric molecules do have rotational Raman spectra. Not all the vibrational mode can be excited by a femtosecond pulse. The pulsewidth of our excitation beam should be less than the half of the vibration period. In this dissertation my excitation pulsewidth is not short enough …
Development Of High-Power Single-Mode Yb-Doped Fiber Amplifiers And Beam Analysis, Steffen Wittek
Development Of High-Power Single-Mode Yb-Doped Fiber Amplifiers And Beam Analysis, Steffen Wittek
Electronic Theses and Dissertations, 2020-2023
High-power fiber laser systems enjoy a widespread use in manufacturing, medical, and defense applications as well as scientific research, due to their remarkable power scalability, high electrical to optical efficiency, compactness and ruggedness. However, single-mode fiber power scaling has stagnated in the past years, primarily due to the onset of nonlinear effects such as stimulated Brillouin/Raman scattering and transverse modal instabilities. This thesis addresses the analysis and mitigation of transverse modal instabilities in high-power fiber amplifiers. I describe the high-power fiber amplifier testbed that I set up to test fibers fabricated in house. I will show our results of a …
Attosecond Transient Absorption Spectroscopy In The Water Window, Andrew Chew
Attosecond Transient Absorption Spectroscopy In The Water Window, Andrew Chew
Electronic Theses and Dissertations, 2020-2023
The push to study the atomic and molecular dynamics at ever smaller time scales has been the main driving force for developing laser systems with ever shorter pulse durations. Thus far, picosecond lasers and femtosecond lasers have been used with great success in femtochemistry to study molecular dynamics such as molecular rotation and vibration, which all occur in the tens to hundreds of femtosecond. To study electron dynamics however, which are on the order of attoseconds, one needs attosecond laser sources to be able to have the time resolution required to probe ultrafast electron dynamics such as AC Stark shifts, …
High-Fidelity Mini-Led And Micro-Led Displays, Yuge Huang
High-Fidelity Mini-Led And Micro-Led Displays, Yuge Huang
Electronic Theses and Dissertations, 2020-2023
Mini-LED and micro-LED are emerging disruptive display technologies, because they can work as local dimmable backlight to significantly enhance the dynamic range of conventional LCDs, or as sunlight readable emissive displays. However, there are still unresolved issues impairing their display fidelity: 1) motion blur on high-resolution, large-size and high-luminance devices, 2) limited contrast ratio on mini-LED backlit LCD (mLED-LCD), 3) relatively high power consumption, and 4) compromised ambient contrast ratio. This dissertation tackles with each of these issues for achieving high display fidelity. Motion blur is caused by slow liquid crystal response time and image update delays. Low-duty ratio operation …
Multi-Parameter Optical Metrology: Quantum And Classical, Walker Larson
Multi-Parameter Optical Metrology: Quantum And Classical, Walker Larson
Electronic Theses and Dissertations, 2020-2023
The insights offered by quantum mechanics to the field of optical metrology are many-fold, with non-classical states of light themselves used to make sensors that surpass the sensitivity of sensors using classical states of light. Unfortunately, this advantage, referred to often as "super-sensitivity" is notoriously fragile, and even the slightest experimental imperfections may greatly reduce the efficacy of the non-classical sensors, sometimes completely obviating their advantage. In my thesis I have shown that the performance of an otherwise ideal two-photon interferometer, which exploits entanglement between photons to make super-sensitive measurements of phase, is crippled by the slightest introduction of decoherence …
Midwave Vs Longwave Infrared Search And Track And Aerosol Scattering Target Acquisition Performance, Steven Butrimas
Midwave Vs Longwave Infrared Search And Track And Aerosol Scattering Target Acquisition Performance, Steven Butrimas
Electronic Theses and Dissertations, 2020-2023
The decision on whether to use a mid wave infrared (MWIR) or long wave infrared (LWIR) sensor for a given task can be a formidable verdict. The scope entails facts about the observable source, the atmospheric interactions, and the sensor parameters within the hardware device. Even when all the individual metrics are known, the combination ultimately determines whether a MWIR or LWIR sensor is more appropriate. Despite the vast number of variables at play, the reduction of inputs through focused studies can provide essential insight into MWIR and LWIR comparisons. This dissertation focuses on the roles of point source target …
Heterogeneous Integrated Photonics For Nonlinear Frequency Conversion And Polarization Diversity, Tracy Sjaardema
Heterogeneous Integrated Photonics For Nonlinear Frequency Conversion And Polarization Diversity, Tracy Sjaardema
Electronic Theses and Dissertations, 2020-2023
Silicon has proven to be one of the materials of choice for many integrated photonic applications. However, silicon photonics is limited by certain material shortcomings. Two shortcomings addressed in this work are zero second-order optical nonlinearity, and the lack of methods available to achieve broadband polarization diversity. Heterogeneous integrated solutions for these shortcomings of silicon photonics are presented in this work. First, nonlinear frequency conversion is demonstrated with thin-film lithium niobate on silicon substrates. The method for reaching the highest-achieved second-harmonic generation conversion efficiency, using active monitoring during periodic poling, is discussed. Additionally, a cascaded approach for generating higher-order harmonics …
Few-Mode Fiber Lasers And Amplifiers, Ning Wang
Few-Mode Fiber Lasers And Amplifiers, Ning Wang
Electronic Theses and Dissertations, 2020-2023
Lasers and amplifiers of high-order spatial modes are useful for a number of applications, including communication, sensing, microscopy, and laser material processing. This dissertation presents the generation and amplification of high-order spatial modes in few-mode fibers (FMFs). In the area of amplification of high-order spatial modes, low-crosstalk amplification among spatial modes is realized in a retro-reflecting few-mode Er-doped fiber amplifier (EDFA) by exploiting the unitary property of the coupling matrix of a symmetric photonic lantern (PL). A small-signal gain larger than 25 dB and crosstalk below -10 dB was achieved over the C-band for a 3-mode EDFA. Such a few-mode …
Parallelized X-Ray Tracing With Gpu Ray-Tracing Engine, Joseph Ulseth
Parallelized X-Ray Tracing With Gpu Ray-Tracing Engine, Joseph Ulseth
Electronic Theses and Dissertations, 2020-2023
X-ray diffraction tomography (XDT) is used to probe material composition of objects, providing improved contrast between materials compared to conventional transmission based computed tomography (CT). In this work, a small angle approximation to Bragg's Equation of diffraction is coupled with parallelized computing using Graphics Processing Units (GPUs) to accelerate XDT simulations. The approximation gives rise to a simple yet useful proportionality between momentum transfer, radial distance of diffracted signal with respect to incoming beam's location, and depth of material, so that ray tracing may be parallelized. NVIDIA's OptiX ray-tracing engine, a parallelized pipeline for GPUs, is employed to perform XDT …