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Optimizing Mixed Reality Simulation To Support Stem Graduate Teaching Assistants In Developing Student-Centered Pedagogical Skills, Constance Doty
Optimizing Mixed Reality Simulation To Support Stem Graduate Teaching Assistants In Developing Student-Centered Pedagogical Skills, Constance Doty
Electronic Theses and Dissertations, 2020-2023
Physics graduate teaching assistants (GTA) often instruct student-centered lab and recitation sections at large universities, creating the opportunity to positively impact students. However, as STEM GTA professional development varies by institution and discipline, GTAs rarely receive feedback about their teaching. In K-12 teacher preparation, "microteaching", where a teacher teaches a lesson to peers acting as students, is used to provide feedback. Research has demonstrated benefits to microteaching in K-12 teacher and STEM GTA preparation, but practicing teachers find microteaching can lack authenticity. Recently, researchers have explored integrating technology, like simulation, in pedagogy training to provide a more authentic training experience. …
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. …
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 …
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 …
Wavelet Particle Hydrodynamics For Less Smooth Flow, Oddny Brun
Wavelet Particle Hydrodynamics For Less Smooth Flow, Oddny Brun
Electronic Theses and Dissertations, 2020-2023
The purpose of this research was to improve the smoothing operation in smoothed particle hydrodynamics, SPH, when the flow of matter is not smooth. Our main focuses are on the kernel selection, identifying the discontinuities in the sequences to be smoothed, and use of the Laplacian as opposed to artificial viscosity for improved physical accuracy. The results show that alternative kernels result in differences in how matter flows. These effects are explained by the kernels' gradient and Laplacian properties. Five alternative kernels were included in our analysis and our SPH-based simulation cases. Further, the sequences to be smoothed by the …
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 …
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 …
Biophysical Analysis Of The Structure And Aggregation Of Amyloid Beta Peptide, Faisal Abedin
Biophysical Analysis Of The Structure And Aggregation Of Amyloid Beta Peptide, Faisal Abedin
Electronic Theses and Dissertations, 2020-2023
Alzheimer's disease (AD) is the major cause of dementia and is characterized by neuronal death and brain atrophy. The amyloid ß (Aß) peptide is tightly associated with neuronal dysfunction during AD, but the molecular mechanism underlying the neurotoxic effect of Aß is poorly understood. Extracellular fibrillar deposits (plaques) of Aß were initially believed to be the cause of AD, but currently there is overwhelming evidence that the prefibrillar Aß oligomers are the major toxic entities. Structural characterization of Aß oligomers and fibrils is important for understanding the structural features determining the toxic potency of the peptide. This project has studied …
Understanding The Mechanisms Of Surface Chemical Reactions By Tracking Unstable Intermediate Species, Md Afjal Khan Pathan
Understanding The Mechanisms Of Surface Chemical Reactions By Tracking Unstable Intermediate Species, Md Afjal Khan Pathan
Electronic Theses and Dissertations, 2020-2023
The detection of intermediate species formed during surface chemical reactions is essential because it can provide critical information about the reaction mechanisms at surfaces and interfaces. Therefore, the overarching goal of this research was to understand the mechanisms of surface catalytic, photocatalytic, and photoinduced reactions by monitoring the intermediate species formed during these reactions. To understand the initial steps of the carbon monoxide hydrogenation reaction on two-dimensional (2D) MoS2 and TaS2 materials, temperature programmed desorption and reaction are employed. Large-area 2D-MoS2 and 2D-TaS2 were prepared on a Cu(111) substrate under ultra-high vacuum conditions via physical vapor deposition. The highly crystalline …
Topology And Megnetism In F-Electron Systems, Firoza Kabir
Topology And Megnetism In F-Electron Systems, Firoza Kabir
Electronic Theses and Dissertations, 2020-2023
Topological insulators are insulators in the bulk but permit spin-polarized electrons to flow on their surface. Till date, non-magnetic topological materials have been extensively studied. However, due to the complex symmetries of magnetic crystals as well as theoretical and experimental difficulties associated with modeling and measuring quantum magnets, only a few magnetic materials have been explored so far. Therefore, by utilizing angle-resolved photoemission spectroscopy (ARPES), along with first-principles calculations, and magneto-transport measurements, we have chosen one doped and four intrinsic magnetic materials to study the interplay between magnetic order and nontrivial topology. First, we have observed a single topological non-trivial …
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 …
Toward In-Situ Nanoscale Imaging And Spectroscopy: Applications In Growth And Catalysis Of Two-Dimensional Materials, Fernand Torres-Davila
Toward In-Situ Nanoscale Imaging And Spectroscopy: Applications In Growth And Catalysis Of Two-Dimensional Materials, Fernand Torres-Davila
Electronic Theses and Dissertations, 2020-2023
New challenges arise with advances in our understanding of two dimensional (2D) materials and their functionalities. The reactivity of defects engineered to drive targeted reactions, such as those relevant to sustainability, or to shape the electronic properties of the host material locally for new applications, such as in nanoelectronics or quantum computing, brings about the need to control the environment of the material and the defect. This is particularly important to advance fundamental studies of catalytic processes to mimic the reaction pathways taking place in large scale reactors at various defect sites. With atomic defects, this constitutes an outstanding challenge …
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 …
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 …
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 …
Enhancement And Evaluation Of Proton Pencil Beam Spot Placement Algorithms, Mahboob Ur Rehman
Enhancement And Evaluation Of Proton Pencil Beam Spot Placement Algorithms, Mahboob Ur Rehman
Electronic Theses and Dissertations, 2020-2023
Intensity modulated proton therapy (IMPT) in the form of pencil beam scanning (PBS) has shown improvement in treatment plan quality as compared to conventional proton and photon-based radiotherapy techniques. However, in IMPT maintaining a sharp lateral dose falloff is crucial for sparing organs at risk (OARs), especially when they are in close proximity to the target volume. The most common approach to improve lateral dose falloff is through the use of physical beam shaping devices, such as brass apertures or collimator-based systems. This work has shown that IMPT can be further improved by implementation of advanced spot placement techniques by …
Development And Surface Science Investigations Of Epitaxial Thin Films Suitable For Elucidating Mechanisms Of Water Formation And Migration On The Moon, Bijoya Dhar
Electronic Theses and Dissertations, 2020-2023
The growth and characterization of epitaxial thin films see ubiquitous use in both research and applications spanning a number of scientific and industrial fields with overlapping interests in materials science. The central theme of this work centers on leveraging the structural control afforded through the ultrahigh vacuum (UHV) approaches to thin-film epitaxy to derive atomically specific structure-chemistry relationships of key importance to various interface-mediated reactions. The first project was aimed at developing gold (Au) and ceria (CeO2) thin films using advanced surface-science techniques. In that project, a thoroughly wetted Au film on Ta metal substrate has been identified. This model …
Modeling And Analysis Of Covid-19 And Dynamical Systems In Biology And Physics, Vladimir Grbic
Modeling And Analysis Of Covid-19 And Dynamical Systems In Biology And Physics, Vladimir Grbic
Honors Undergraduate Theses
In this paper, we study various examples of dynamical systems found in nature and extract the necessary concepts to build upon. Then, we develop and propose a new deterministic model for COVID-19 propagation. Our model should serve two purposes. First, we will approximate the infected and deceased individuals after a given time during the pandemic. Then, using a linearized subsystem describing infectious compartments about the disease- free equilibrium (DFE), we will determine the basic reproductive number (R0) by the next-generation matrix method.
Plasmonic Properties Of Nanopatterned Graphene, Muhammad Waqas Shabbir
Plasmonic Properties Of Nanopatterned Graphene, Muhammad Waqas Shabbir
Electronic Theses and Dissertations, 2020-2023
Graphene is an atomically thin two-dimensional material with carbon atoms arranged in a honeycomb lattice. It has been successfully mechanically exfoliated from graphite and characterized in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester, UK. While suspended graphene holds the world record in mobility exceeding 100,000 cm2/Vs, which means that graphene could increase the operating frequency of electronic devices up to the THz regime. For example, imaging computer chips running at a few THz frequency, which would be about 1000 times faster than current chips. However, there are two main obstacles for using graphene in electronics …
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 …
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 …
Qualitative Reconceptualizations Of Success In Physics From A Feminist Lens, Brian Zamarripa Roman
Qualitative Reconceptualizations Of Success In Physics From A Feminist Lens, Brian Zamarripa Roman
Electronic Theses and Dissertations, 2020-2023
To address the critical issue of the underrepresentation of women in physics, the Physics Education Research community has focused on exploring the factors contributing to student success; however, few studies have explored the meaning of success in physics as seen by women and other marginalized populations. This study, guided by Feminist Standpoint Theory and Critical Race Nepantlera Methodologies, incorporates qualitative methods to explore the central question, "how do women in physics conceptualize the meaning of success in physics?" We begin with an analysis of metaphors of success in physics constructed by nine women studying physics at a single institution, followed …
Exploring New Materials As Promising Electrocatalysts For The Generation Of A Clean And Renewable Energy Source, Tyler Campbell
Exploring New Materials As Promising Electrocatalysts For The Generation Of A Clean And Renewable Energy Source, Tyler Campbell
Electronic Theses and Dissertations, 2020-2023
This work presents the research of myself, my advising professor, and our collaborators in first-principles studies of several catalytic materials for improving the efficiency and economics of hydrogen fuel cells, focusing on the oxygen reduction reaction (ORR) at the cathode, CO removal and the hydrogen oxidation reaction (HOR) at the anode, and the redox reactions used for water splitting through photocatalysis. We use a computational design approach to analyze the reaction thermodynamics, applying density functional theory (DFT) for most calculations. We find that, through a subversion of the linear scaling approximation for surface reactivity, an Au monolayer deposited on the …
Dual Beam Frequency Comb Ftir Spectroscopy, Connor Kelly
Dual Beam Frequency Comb Ftir Spectroscopy, Connor Kelly
Electronic Theses and Dissertations, 2020-2023
A visible and Infrared (IR) range dual beam frequency comb Fourier transform spectrometer was developed. Using dual mode-locked Ti:Sapphire lasers a comb-interferogram was generated in the visible range. This spectrum was calculated and used to measure the transmittance of a Nd-doped crystal. The system was further developed to generate an IR interferogram by Difference Frequency Generation (DFG) using a Gallium Selenide (GaSe) crystal placed in the mode-locked pump beam. Numerical work was done to calculate the expected DFG spectrum confirming the necessary IR range can be reached. This has been conducted in support of an IR holographic spectroscopic microscopy spatial …
Unusual Superconductivity In Topological Nodal Line Semimetal, Riffat Munir
Unusual Superconductivity In Topological Nodal Line Semimetal, Riffat Munir
Electronic Theses and Dissertations, 2020-2023
Unconventional superconductivity differs from the conventional one by the pairing mechanism. In conventional or s wave superconductor electrons with opposite spin and momentum form cooper pair and superconductivity occurs as a result of electron phonon interaction. In the unconventional superconductor pairing mechanism is different than that of conventional one , for example p wave pairing where electrons with similar direction of spin forms the cooper pair. Unconventional superconductivity has been observed in systems such as heavy fermion,cuprates, iron based superconductors etc. In recent years topological superconductivity has gained attention due to the combination of topological states in the band sturucture …
Superconductivity And Topological Properties In A Topological Semimetal, K A M Hasan Siddiquee
Superconductivity And Topological Properties In A Topological Semimetal, K A M Hasan Siddiquee
Electronic Theses and Dissertations, 2020-2023
Topological superconductors (TSCs) in which superconductivity and topological properties are combined are characterized by topologically protected gapless states in the superconducting gaps. Realized in the gapless states of TSCs, Majorana fermions, which are particles and their own antiparticles, have crucial importance in quantum computation and spintronic device applications because of the exotic nature. Despite extensive study for the confirmation of TSCs, the observation of Majorana fermions in bulk superconductors has not been settled yet. Recently, the binary stannide semimetal CaSn3 with a cubic structure has been proposed to be a promising candidate for realizing topological superconductivity. In this dissertation, to …
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 …
Chemical Vapor Deposition Growth Of Transition Metal Dichalcogenides And Their Heterostructure Integration, Sajeevi Sankalpani Withanage
Chemical Vapor Deposition Growth Of Transition Metal Dichalcogenides And Their Heterostructure Integration, Sajeevi Sankalpani Withanage
Electronic Theses and Dissertations, 2020-2023
Two-dimensional transition metal dichalcogenides (TMDs) are of great interest for the discovery of many novel physics owing to their extraordinary electrical, optical, mechanical properties as well as many promising applications including heterojunctions. To realize the overreaching goals of these materials, it is important to develop scalable growth techniques and investigate the role of different growth parameters on the resulting material properties. In this dissertation, I study, (i) controllable and reproducible growth of monolayer molybdenum disulfide (MoS2) via chemical vapor deposition (CVD), (ii) the role of growth temperature on the properties of large area MoS2 thin films grown via thermal vapor …
Structure Of Unmodified And Pyroglutamylated Amyloid Beta Peptide In Lipid Membranes, Rowan Hassan
Structure Of Unmodified And Pyroglutamylated Amyloid Beta Peptide In Lipid Membranes, Rowan Hassan
Honors Undergraduate Theses
Alzheimer's Disease (AD) is a devastating neurodegenerative disease that is characterized by brain atrophy, neuronal and synaptic loss, cognitive decline, trouble handling activities of daily life, and ultimately leads to death. Worldwide, at least 30 million people suffer from AD, with 5.8 million suffering in the US alone. Despite extensive basic and clinical research, the underlying molecular mechanisms behind AD remain largely unknown. There are four FDA-approved compounds are used for alleviating symptoms but have no curative potency. The first potentially disease-modifying AD drug, aducanumb, was approved by FDA in June 2021. The main histopathological traits of AD are the …
Photoemission Investigation Of Topological Quantum Materials, Klauss M. Dimitri
Photoemission Investigation Of Topological Quantum Materials, Klauss M. Dimitri
Honors Undergraduate Theses
Topological insulators (TIs) are a class of quantum materials, which behave as insulators in the bulk, yet possess gapless spin-polarized surface states, which are robust against nonmagnetic impurities. The unique properties of TIs make them attractive not only for studying various fundamental phenomena in condensed matter and particle physics, but also as promising candidates for applications ranging from spintronics to quantum computation. Within the topological insulator realm, a great deal of focus has been placed on discovering new quantum materials, however, ideal multi-modal quantum materials have yet to be found. Here we study alpha-PdBi2, KFe2Te2, and DySb compounds including others …