Physics Commons^™

Supercontinuum Generation With A Ti: Sapphire Laser And Photonic Crystal Fiber, Joseph Lange

Celebrating Scholarship and Creativity Day (2018-)

A broad spectrum of visible light was produced by focusing the 50-fs, 800-nm, 5-nJ pulses from an unamplified Ti:sapphire laser into a 20-cm-long photonic crystal fiber. A prism pair was used to compensate for material dispersion of the system. Different focusing methods were investigated including beam telescopes and lenses of various focal lengths. A 3X beam expander telescope near the laser output and a 3-cm focal length achromatic lens after the prism pair were found to work best for coupling the light into the fiber which has a core diameter of 1.7 μm.

Motion History Images: A New Method For Tracking Microswimmers In 3d, Max Riekeles, Hadi Albalkhi, Megan Marie Dubay, Jay Nadeau, Christian A. Lindensmith

Physics Faculty Publications and Presentations

Quantitative tracking of rapidly moving micron-scale objects remains an elusive challenge in microscopy due to low signal-to-noise. This paper describes a novel method for tracking micron-sized motile organisms in off-axis Digital Holographic Microscope (DHM) raw holograms and/or reconstructions. We begin by processing the microscopic images with the previously reported Holographic Examination for Life-like Motility (HELM) software, which provides a variety of tracking outputs including motion history images (MHIs). MHIs are stills of videos where the frame-to-frame changes are indicated with color time-coding. This exposes tracks of objects that are difficult to identify in individual frames at a low signal-to-noise ratio. …

Reed Research Reactor Neutron Beam Characterization And Analysis, Vee Bartko, Jerry Newhouse

Student Research Symposium

Using neutron activation analysis of 99% pure gold foils, the authors characterize the neutron dose and shape of the neutron beam at the Reed Research Reactor (RRR). The experimental procedure followed extensive modeling in Monte Carlo N-Particle (MCNP) and Tool for Particle Simulation (TOPAS) simulations, in which the beam was projected to be roughly collimated. The shape, defined in terms of neutron flux, was measured by placing the foils directly on top of the neutron beam cap at powers of 1, 5, and 10 kilowatts. The flux was then converted to neutron dose via the Nuclear Regulatory Commission's neutron fluence …

Development Of A Two-Photon Laser Scanning Microscope, Jess Hollenbaugh

Student Research Symposium

The objective of this project was to convert a Sarastro 2000 confocal laser scanning microscope into a system capable of imaging using two-photon excitation (TPE) fluorescence for the use of the PSU biology department. TPE microscopy operates on the ability of fluorophores to accept two photons each with half the energy of a desired transition in a single quantum event via a virtual energy state and then emit a higher energy photon upon relaxation. This is preferable to single-photon excitation (SPE) due to the lower energy photons causing less damage to delicate biological samples. The adaptation process included physically altering …

Neutron Time Of Flight Spectrometry As A Diagnostic Tool For Inertial Electrostatic Confinement Fusion Plasmas, Andrew H. Dempsey, Erik J. Sanchez

Student Research Symposium

Inertial electrostatic confinement (IEC) is a method for achieving fusion of light nuclei wherein ions are injected into a spherically symmetric system of concentric electrodes. When the innermost electrode is held at negative high voltage with respect to the outer electrode, ions injected into the reactor at cathode (ground) potential accelerate toward the anode where they may undergo collisions with sufficient energy to overcome Coulomb repulsion and achieve nuclear fusion. The most commonly used IEC fusion fuels are deuterium-deuterium (D-D) and deuterium-tritium (D-T). Both fuels undergo fusion reactions that result in production of fast neutrons with distinct energies. Neutron production …

Going Down An Incline With Chatgpt, Corey R. Sissons

Student Research Symposium

In our Large Language Model (LLM) research, examining ChatGPT 4, we devised a physics problem involving an object descending an inclined plane. Through variations in terminology such as "rolling," "sliding," "solid sphere," "hollow sphere," "wooden ramp," "no-slip ramp," and more, we sought to evaluate LLM responses for different scenarios. Our analysis aimed to discern whether the LLM’s answers exhibited expertise in the field of physics. This experiment sheds light on LLM’s ability to give accurate and precise physics answers as well as variation in responses to nuanced changes in problem formulation. This provides valuable insights into its proficiency and potential …

Comparison Of The Fluorescence Of Bulk Cadmium Sulfide And Cadmium Sulfide Nanoparticles, Jacob Goranson

Celebrating Scholarship and Creativity Day (2018-)

The fluorescence of bulk cadmium sulfide and cadmium sulfide nanoparticles were compared. This was done using an 800-nm, unamplified Ti:sapphire laser producing 50-fs pulses. The pulses were frequency doubled using a beta barium borate (BBO) crystal. The 400-nm beam was used to induce fluorescence in the nanoparticles, while the original 800-nm beam was used to induce fluorescence in the bulk CdS by two-photon absorption. The bulk CdS showed a single fluorescent peak at 523 nm. The nanoparticles showed fluorescence at various wavelengths across the visible spectrum. In general, the nanoparticles showed a broad fluorescent spectrum between 500 nm and 750 …

A Realist Interpretation Of Unitarity In Quantum Gravity, Indrajit Sen, Stephon Alexander, Justin Dressel

Mathematics, Physics, and Computer Science Faculty Articles and Research

Unitarity is a difficult concept to implement in canonical quantum gravity because of state non-normalisability and the problem of time. We take a realist approach based on pilot-wave theory to address this issue in the Ashtekar formulation of the Wheeler–DeWitt equation. We use the postulate of a definite configuration in the theory to define a global time for the gravitational-fermionic system recently discussed in Alexander et al (2022 Phys. Rev. D 106 106012), by parameterising a variation of a Weyl-spinor that depends on the Kodama state. The total Hamiltonian constraint yields a time-dependent Schrodinger equation, without semi-classical approximations, which we …

Signal Processing Algorithms For Doppler Lidar Sensors, Samantha Grubb

Physics and Astronomy Honors Papers

Light detection and ranging (LiDAR) is a remote sensing technology that obtains relative distance and velocity measurements between a sensor and a defined target by using light transmitted and received from the target. FMCW Doppler LiDAR, a particular variant of LiDAR, functions by analyzing the frequency shift in the reflected light to determine the target's range and velocity. This technology plays a crucial role across various sectors including defense, aerospace, and automotive. This paper presents signal processing algorithms designed to optimize data obtained from Doppler LiDAR sensors. By applying various window functions to time domain data, the Signal-to-Noise Ratio (SNR) …

Analyzing Atmospheric Gravity Waves Over Antarctica And Visualizing Machine Learning Data, Anastasia N. Brown

Physics Capstone Projects

In an effort to streamline the identification of "clean" windows of airglow images in all sky imager data for the ANGWIN experiment, we have developed a Light Gradient Boosted Machine (LightGBM) learning algorithm that sorts "clean" (marked as 0) wave images from "obscured" (marked as 1) images. These "clean" windows are then processed and undergo FFT-spectrum analysis. We have already successfully created LightGBM models that accurately sort through images taken at the Davis, McMurdo, and Halley research stations in Antarctica. Imager data from the Davis and McMurdo station has been fully processed from the years 2012 to 2022 with clean …

Evaluation Of An End-To-End Radiotherapy Treatment Planning Pipeline For Prostate Cancer, Mohammad Daniel El Basha, Court Laurence, Carlos Eduardo Cardenas, Julianne Pollard-Larkin, Steven Frank, David T. Fuentes, Falk Poenisch, Zhiqian H. Yu

Dissertations & Theses (Open Access)

Radiation treatment planning is a crucial and time-intensive process in radiation therapy. This planning involves carefully designing a treatment regimen tailored to a patient’s specific condition, including the type, location, and size of the tumor with reference to surrounding healthy tissues. For prostate cancer, this tumor may be either local, locally advanced with extracapsular involvement, or extend into the pelvic lymph node chain. Automating essential parts of this process would allow for the rapid development of effective treatment plans and better plan optimization to enhance tumor control for better outcomes.

The first objective of this work, to automate the treatment …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Divergence-Free Tensor Densities In Two Dimensions, Tyler Hansen

All Graduate Theses and Dissertations, Fall 2023 to Present

In physics, a common method for exploring the way a physical system changes over time is to look at the system’s energy. Roughly speaking, the energy in these systems are either motion-based (kinetic energy, a bullet in flight) or position-based (potential energy, a rock sitting at the top of a hill). The difference between the system’s total kinetic and potential energies is quantified by an expression called the Lagrangian. Using a special procedure, this Lagrangian is massaged to produce a group of equations called the Euler-Lagrange equations; if the initial configuration of the system is provided, the solution to these …

College Of Natural Sciences Newsletter, Spring 2024, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 1 Dean's Message
Page 2 New Faculty and New Club on Campus
Page 3 2024 URSCAD Awards
Page 4 Day of Scholars 2024
Page 5 SDSU's First Representation at the Association for Anatomy's 2024
Annual Conference
Page 6-7 2024 Honor's College Convocation
Page 8 Other Student Activities
Page 9 Faculty Awards
Page 10-11 Other News
Page 12 2024 Drone Day and American Association of Geographers Convention - Hawaii
Page 13 55th Annual Geography Convention
Page 14 2024 Stethoscope Ceremony
Page 15 Open PRAIRIE Data

Improving The Scalability Of Neural Network Surface Code Decoders, Kevin Wu

Undergraduate Honors Theses

Quantum computers have recently gained significant recognition due to their ability to solve problems intractable to classical computers. However, due to difficulties in building actual quantum computers, they have large error rates. Thus, advancements in quantum error correction are urgently needed to improve both their reliability and scalability. Here, we first present a type of topological quantum error correction code called the surface code, and we discuss recent developments and challenges of creating neural network decoders for surface codes. In particular, the amount of training data needed to reach the performance of algorithmic decoders grows exponentially with the size of …

Modeling The Neutral Densities Of Sparc Using A Python Version Of Kn1d, Gwendolyn R. Galleher

Undergraduate Honors Theses

Currently, neutral recycling is a crucial contributor to fueling the plasma within tokamaks. However, Commonwealth Fusion System’s SPARC Tokamak is expected to be more opaque to neutrals. Thus, we anticipate that the role of neutral recycling in fueling will decrease. Since SPARC is predicted to have a groundbreaking fusion power gain ratio of Q ≈ 10, we must have a concrete understanding of the opacity
and whether or not alternative fueling practices must be included. To develop said understanding, we produced neutral density profiles via KN1DPy, a 1D kinetic neutral transport code for atomic and molecular hydrogen in an ionizing …

Dimensionlessly Comparing Hydrogen And Helium Plasmas At Lapd, Lela Creamer

Undergraduate Honors Theses

This project compares the hydrogen and helium gas puff plasmas created at the Large Plasma Device (LAPD) using dimensionless numbers to determine the extent to which the turbulence pattern can be explained by plasma physics. Since turbu- lence tends to dissipate energy and particles in a plasma, it can cause problems for fusion reactors by reducing their efficiency. With a better understanding of turbu- lence’s causes and behavior, some of this energy loss could potentially be avoided. In recent experiments at LAPD, an unexpectedly high amount of turbulence was de- tected when helium was used to create the plasma, which …

Identifying Transitions In Plasma With Topological Data Analysis Of Noisy Turbulence, Julius Kiewel

Undergraduate Honors Theses

Cross-field transport and heat loss in a magnetically confined plasma is determined by turbulence driven by perpendicular (to the magnetic field) pressure gradients. The heat losses from turbulence can make it difficult to maintain the energy density required to reach and maintain the conditions necessary for fusion. Self-organization of turbulence into intermediate scale so-called zonal flows can reduce the radial heat losses, however identifying when the transition occurs and any precursors to the transition is still a challenge. Topological Data Analysis (TDA) is a mathematical method which is used to extract topological features from point cloud and digital data to …

Impact Of Property Covariance On Cluster Weak Lensing Scaling Relations, Zhuowen Zhang, Arya Farahi, Daisuke Nagai, Erwin T. Lau, Joshua Frieman, Marina Ricci, Anja Von Der Linden, Hao-Yi Wu, Lsst Dark Energy Science Collaboration

Physics Faculty Publications and Presentations

We present an investigation into a hitherto unexplored systematic that affects the accuracy of galaxy cluster mass estimates with weak gravitational lensing. Specifically, we study the covariance between the weak lensing signal, ΔΣ, and the ‘true’ cluster galaxy number count, N_gal, as measured within a spherical volume that is void of projection effects. By quantifying the impact of this covariance on mass calibration, this work reveals a significant source of systematic uncertainty. Using the MDPL2 simulation with galaxies traced by the SAGE semi-analytic model, we measure the intrinsic property covariance between these observables within the three-dimensional vicinity of …

Encapsulated 2d Materials And The Potential For 1d Electrical Contacts, Sarah Wittenburg

Physics Undergraduate Honors Theses

The utilization of two-dimensional materials and heterostructures, particularly graphene and hexagonal boron nitride, have garnered significant attention in the realm of nanoelectronics due to their unique properties and versatile functionalities. This study focuses on the synthesis and fabrication processes of monolayer graphene encapsulated between layers of hBN, aiming to explore the potential of these heterostructures for various electronic applications. The encapsulation of graphene within hBN layers not only enhances device performance but also shields graphene from environmental contaminants, ensuring long-term stability. Experimental techniques, including mechanical exfoliation and stamp-assisted transfer, are employed to construct three-layer stacks comprising hBN-graphene-hBN. The fabrication process …

Measurement Of Transmission Efficiency Of Blue Light Blocking Devices, Jada Lee

Honors Theses

Technology and light sources have experienced a revolution in recent years leading to the production of light emitting diode (LED) bulbs. White-light LED bulbs undergo degradation over time, leading to a rise in color temperature and a proportional increase in the emission of blue light from these bulbs. The small size of LEDs makes them the optimal choice for electronic devices because of their limited screen size. This means that blue light now exists in red, green, and blue solid-state illumination systems that did not exist a decade ago. It is debated if blue light induces toxic effects on the …

A Comprehensive Investigation Of The Influence Of Geometric Structure On The Shape Memory Performance Of Nafion, Jade Thomas

Physics Undergraduate Honors Theses

While perfluorosulfonic acid (PFSA) membranes have primarily been used in fuel cells due to their chemical, thermal, and mechanical stability, one PFSA, Nafion, boasts two unique characteristics: a broad glass transition (~55 °C to 130 °C) and a temperature-persistent electrostatic network. The combination of these two characteristics endows Nafion with exceptional shape memory properties – the ability of a material to morph and transform into pre-programmed shapes when exposed to an external stimulus – with enhanced permanent shape memorization, and a potentially near-infinite number of temporary shape memorization. This study focused on expanding the base of knowledge surrounding Nafion’s shape …

A Comprehensive Investigation Of The Influence Of Geometric Structure On The Shape Memory Performance Of Nafion, Jade Thomas

Mechanical Engineering Undergraduate Honors Theses

While perfluorosulfonic acid (PFSA) membranes have primarily been used in fuel cells due to their chemical, thermal, and mechanical stability, one PFSA, Nafion, boasts two unique characteristics: a broad glass transition (~55 °C to 130 °C) and a temperature-persistent electrostatic network. The combination of these two characteristics endows Nafion with exceptional shape memory properties – the ability of a material to morph and transform into pre-programmed shapes when exposed to an external stimulus – with enhanced permanent shape memorization, and a potentially near-infinite number of temporary shape memorization. This study focused on expanding the base of knowledge surrounding Nafion’s shape …

Exploring The Coronal Magnetic Field With Galactic Cosmic Rays: The Sun Shadow Observed By Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.

Michigan Tech Publications, Part 2

Galactic cosmic rays (GCRs) are charged particles that reach the heliosphere almost isotropically in a wide energy range. In the inner heliosphere, the GCR flux is modulated by solar activity so that only energetic GCRs reach the lower layers of the solar atmosphere. In this work, we propose that high-energy GCRs can be used to explore the solar magnetic fields at low coronal altitudes. We used GCR data collected by the High-Altitude Water Cherenkov observatory to construct maps of GCR flux coming from the Sun’s sky direction and studied the observed GCR deficit, known as Sun shadow (SS), over a …

Proof-Of-Concept For Converging Beam Small Animal Irradiator, Benjamin Insley

Dissertations & Theses (Open Access)

The Monte Carlo particle simulator TOPAS, the multiphysics solver COMSOL., and

several analytical radiation transport methods were employed to perform an in-depth proof-ofconcept

for a high dose rate, high precision converging beam small animal irradiation platform.

In the first aim of this work, a novel carbon nanotube-based compact X-ray tube optimized for

high output and high directionality was designed and characterized. In the second aim, an

optimization algorithm was developed to customize a collimator geometry for this unique Xray

source to simultaneously maximize the irradiator’s intensity and precision. Then, a full

converging beam irradiator apparatus was fit with a multitude …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Technology Development And Materials Research To Enable A Sustainable D-T Fusion Energy Fuel Cycle, Brenda L. Garcia-Diaz, David Babineau, James Klein, Robert Allgood, George Larsen, Holly B. Flynn, Dale Hitchcock, Tim Krentz, Chris Dandeneau, Lucas Angelette, Robert Sindelar

Journal of the South Carolina Academy of Science

No abstract provided.

Time Resolved X-Ray Spectroscopy Of Highly Charged Ar, Nd, And Pr, Timothy Burke

All Dissertations

Highly Charged Ions (HCIs) may be considered ideal mini-laboratory in which one can study the physics of matter and light in an environment of high internal electric field that can not be recreated with standard lab equipment. The remaining electron(s) exist in the extremely large electric field of the nucleus and therefore measurements of electronic transitions in these systems provide stringent tests of our understanding of physics in extreme conditions. Quantum electrodynamics (QED) despite being a powerful theory exhibits large discrepancies for systems under extreme conditions. The work here investigates the atomic properties within non-Maxwellian plasmas. The HCI plasmas studied …

Oscillations Of Capillary Surfaces With Volume And Edge Effects, Dingqian Ding

All Dissertations

Capillary surfaces are defined by an interface endowed with surface tension that is partially supported by a solid substrate and are susceptible to oscillations reflecting a balance between fluid inertia and the restorative force of surface tension. The wave dynamics strongly depend upon volume change within the domain and edge effects through the boundary conditions applied at the contact-line formed at the liquid-gas-solid interface, while the spatial wave structure conforms to the geometry of the capillary surface. This dissertation develops mathematical models to address these effects for several canonical capillary surfaces, which are organized into two parts that are focused …

Numerical Simulation Of Laser Induced Elastic Waves In Response To Short And Ultrashort Laser Pulses., Alireza Zarei

All Dissertations

In an era of intensified market competition, the demand for cost-effective, high-quality, high-performance, and reliable products continues to rise. Meeting this demand necessitates the mass production of premium products through the integration of cutting-edge technologies and advanced materials while ensuring their integrity and safety. In this context, Nondestructive Testing (NDT) techniques emerge as indispensable tools for guaranteeing the integrity, reliability, and safety of products across diverse industries.

Various NDT techniques, including ultrasonic testing, computed tomography, thermography, and acoustic emissions, have long served as cornerstones for inspecting materials and structures. Among these, ultrasonic testing stands out as the most prevalent method, …