Atomic, Molecular and Optical Physics Commons^™

Vorticies In The Nonlinear Optical Fluid, Patrick C. Ford

Electronic Theses and Dissertations

In this dissertation, we review the dynamics of the propagation of a laser through a nonlinear medium, and the dynamics of a self-interacting superfluid phase, and show a mathematical analogy between them. We identify an equivalence that allows direct comparison of the properties and dynamics of the optical fluid with those of the Bose-Einstein condensate. Next, we describe some experimental techniques and methods for data capture and analysis on the way to presenting a novel experimental apparatus that has allowed us to study non-equilibrium nonlinear vortex dynamics in the optical fluid, and that will allow more general future studies of …

How Does Honey Make Gold Nanoparticles? Optical Analysis Of The Effects Of Temperature And Composition, Lydia Alvarnaz, Davon Ferrara Phd

SPARK Symposium Presentations

In recent years, with an increasing interest in green chemistry, there has been an effort to find and understand synthesis methods using biologically-produced reducing and capping agents to produce stable gold nanoparticles (GNPs). Previous research using honey has shown this substance is a viable reducing agent in the formation of nanoparticles but have not looked at the stability of the colloidal gold nanoparticles. In this work, gold nanoparticles were reduced from an aqueous solution of gold chloroauric acid and a solution of varying concentrations of honey and water. The formation of NPs was analyzed using UV-Visible transmission spectroscopy to confirm …

On Static Equilibrium State Of An Electron-Positron Pair Interacting By Electrostatic And Magnetic Forces, Polievkt Perov, Natasha Perova-Mello

College of Arts & Sciences Faculty Works

An electron-positron pair can be in static equilibrium where the magnetic torque is zero and the attractive Coulomb’s force between unlike charges and the repelling force between the spin magnetic moments of these two particles balance each other out. An electron-positron pair near the equilibrium position can be modeled as an oscillator consisting of two masses on a spring. The calculations of the equilibrium distance, the effective “electromagnetic spring constant”, and the frequency of oscillations of an electron-positron pair near the equilibrium are presented. The calculations might be useful for the students in their studies of electricity, magnetism, and particle …

Transfer Efficiencies Of Surface-To-Surface Transport Of Micron-Sized Actinide Surrogate Particles, Austin R. Powell

Theses and Dissertations

Particle effluent of varying sizes is released during routine activities within laboratory environments and these particles can come in contact with a wide range of surfaces. Particles of micron size or smaller can be especially pervasive and can transfer between multiple subsequent surfaces, leading to the progressive contamination of a laboratory. Understanding the transport dynamics of micron sized particles will help inform facility personnel of the possibility of contamination by these potentially hazardous materials of interest. In this research, the transfer efficiency of micron sized surrogate actinide particles (Europium-doped Gadolinium Oxysulfide (EGOS)) is measured for multiple materials, between two particle …

Numerical Studies Of Semiclassical Light Storage Using The Coherent Atomic Transfer Function, Zachary T. Johnson

Theses and Dissertations

Quantum communication through photons relies on photonic storage to preserve quantum states. However, when photons interact with matter, quantum information becomes distorted. A recently developed semi-classical analytical model predicts output light pulses from an electromagnetically induced transparency (EIT) system. Using the predictions, the model known as the Coherent Atomic Transfer (CAT) Function, is capable of predicting the stored pulse or reconstructing the original pulse. Using numerical convolution and deconvolution with the CAT function as an analog of the point spread function of Fourier optics can provide insights on the effects of EIT storage on the retrieved pulse. Blind deconvolution is …

Isotopic Analysis Of Lithium Hydroxide Monohydrate Using Laser-Induced Breakdown Self-Reversal Isotopic Spectrometry (Libris) And Machine Learning, Madison R. Moran

Theses and Dissertations

High-resolution Laser-Induced Breakdown Self-Reversal Isotopic Spectrometry (LIBRIS) is implemented to record the 15.8 pm Li I 670.8 nm isotopic shift in LiOH · H₂O samples of varying 6, 7Li abundance. A simple univariate linear regression demonstrates an acquired isotopic shift of 13.813 ± 1.21 pm in samples varying from 3 to 95 ⁶Li at%. Supervised machine learning regressions are trained on self-reversal wavelength locations in order to quantify ⁶Li abundance. A stacked ensemble using two base learners yields the superlative characterization of 6Li abundance with RMSE of 5.66 at% and detection limit of 18.8 at%. Using …

Implications Of Magnetic Evolution On Coronal Loop Thermal Variation Prior To Solar Flares, Kara L. Kniezewski

Theses and Dissertations

Solar flares are intense bursts of electromagnetic radiation, which occur due to a rapid destabilization and reconnection of the magnetic field. While flares are a magnetic phenomena, very little attention has been paid to thermal conditions in the corona prior to flare onset. This study serves as a follow-on to Kniezewski et al., 2024, where the EUV emission from coronal loops was observed to vary substantially and without any coherence between channels before 53 off-limb flares. These variations suggest multiple mechanisms within the coronal magnetic field are responsible for heating fluctuations. Here, the 3D magnetic field is modeled using a …

On The Exploration Of Crystallographic Anisotropy And Defects In Shock Loading Using Molecular Dynamics, Benjamin P. Helman

Theses and Dissertations

The impact of crystallographic orientation, grain boundaries, and vacancies on the shock behavior of aluminum was investigated using molecular dynamics simulations. Shock loading in the [001], [011], and [111] directions was explored, revealing anisotropic behavior in shock speed, melting, dislocation density, and unique phase changes. The Hugoniot elastic limit in the [100], [110], and [111] directions was calculated as 23.2 GPa, 24 GPa, and 18.4 GPa respectively. These results were found to be an order of magnitude larger than the compressive yield strength computed at equilibrium. Additionally, metastable melting in the [011] and [111] directions occurred roughly 1000 K below …

Material Classification With Spectropolarimetric Lidar, Alexander J. Watson

Theses and Dissertations

A method for characterizing unknown targets using a hyperspectral polarimetric light detection and ranging (LiDAR) system is presented. Light reflected from manmade objects tends to be more polarized than light reflected from objects in the natural world. As such, polarization measurements can be used in remote sensing applications to differentiate artificial and natural objects. Previous works have attempted to characterize objects through passive polarimetric imagery. Methods developed by Cain and Lemaster and Cunningham facilitate reconstruction of the Stokes Vector from returning light. Martin used multispectral polarimetry to classify targets when the angle of incidence (AOI) is close to 0º. Here, …

Convergent Close-Coupling Approach To Electron Scattering On H3+ : Scattering Dynamics And Dissociative Processes, Reese K. Horton, Michael V. Pak, Igor Bray, Dmitry V. Fursa

Faculty Publications

Cross sections for electron impact dissociative excitation and ionization in scattering on vibrationally excited levels of the ground electronic state of H₃⁺, D₃⁺, and T₃⁺ are reported in the energy range of 8–1000 eV. Calculations have been performed using a newly developed version of the molecular convergent close-coupling code. Convergence of the cross sections with the size of the projectile partial-wave and close-coupling expansions is examined. Branching ratios and cross sections for the yields of D₂⁺ and D⁺ from dissociative excitation of D₃⁺ are presented and isotope …

Convergent Close-Coupling Approach To Electron Impact Dissociation Of The Polyatomic Molecule H 3 + And Its Isotopologues, Reese K. Horton, Michael V. Pak, Igor Bray, Dmitry V. Fursa

Faculty Publications

Cross sections for electron impact dissociative excitation and ionization in scattering on vibrationally excited levels of the ground electronic state of H₃⁺ and its isotopologues are reported in the energy range of 8 to 1000 eV. Calculations have been performed using a newly developed version of the molecular convergent close-coupling code. Cross sections for total dissociative excitation, ionization yielding atomic fragments such as D⁺, and the total inelastic cross section are presented. Good agreement with available experiments has been demonstrated.

Explorations Of Dna-Single-Walled Carbon Nanotube Interactions To Develop Multiplexed Molecularly Specific Biosensors For Inflammation, Amelia K. Ryan

Dissertations and Theses

Inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-12 (IL-12) are central regulators of immune signaling and key biomarkers of disease, yet existing assays for their detection remain slow, invasive, and lack multiplexing ability. This dissertation advances the development of single-walled carbon nanotube (SWCNT) optical nanosensors capable of real-time, multiplexed, and molecularly specific cytokine detection through innovative use of single-stranded DNA (ssDNA) interfaces.

First, an IL-6-specific DNA aptamer was employed as both a dispersing agent and recognition probe for SWCNT fluorescence sensing. Sequence modifications, including anchor domains, truncations, and thermally induced refolding, were systematically tested to optimize sensitivity and selectivity. The …

Design And Construction Of An Affordable Adjustable Repetition Rate Optical Frequency Comb, Christopher Latchford

Physics, Astronomy and Geophysics Honors Papers

Two different adjustable repetition rate optical frequency combs were designed and constructed with off-the-shelf components, including several improvements to established erbium fiber designs. These designs were assembled at a fraction of the cost of a commercial comb. Both combs were constructed with a repetition rate of roughly 100 MHz, with one combs tuning range being 2 MHz and the others being 3 MHz. These combs followed different designs, the first being a modification of an established nonlinear polarization rotation (NPR) design, the second being a modification to a “figure 9” design. A stabilization control loop for frep achieved long-term drifts …

Quantum-Mechanical Definition Of The Classical Scalar Potential In Schrödinger-Pauli And Schrödinger Theory, Viraht Sahni

Publications and Research

According to the Bohr correspondence principle, the external temporal scalar potential in the classical equation of motion is replicated in quantum theory as a multiplicative operator. An equivalent quantum-mechanical definition of the scalar potential in Schrödinger-Pauli/Schrödinger theory is provided. The potential is a known universal functional of the wave function. At each instant of time, it is the work done in a conservative “classical” field representative of internal properties of the system: Pauli and Coulomb correlations, kinetic effects, the density, the Lorentz force, an internal magnetic component, and the current density response. The Hamiltonians are thus rewritten in a …

Collision-Induced Absorption Spectra Of N₂ And Ch₄, Ryan M. Johnson, Peter F. Bernath, Brant Billinghurst, Jianbao Zhao

Chemistry & Biochemistry Faculty Publications

Collision-induced spectra are essential for radiative transfer modeling of Titan's atmosphere. We present experimental spectra of nitrogen–methane mixtures with an accompanying fit of N₂-CH₄ collision-induced absorption in the 30–400 cm⁻¹ region at about 130 K. We found a peak absorption of 2.30 × 10⁻⁵ cm⁻¹ amagat⁻² at 75 cm⁻¹ and a secondary peak of 1.35 × 10⁻⁵ c⁻¹ amagat⁻² at 206.5 cm⁻¹, which agrees with previous studies. Our work does not support the suggestion that N₂-CH₄ CIA in the far-infrared should be increased by about 50%, as suggested by spectroscopic modeling of Titan using data from A. Borysow & C. …

Momentum Imaging Of Electrons And Recoil Ions From Anion-Neutral Interactions In A Cryogenic Ion Storage Ring, F. Herrmann, W. Zhang, M. Schulz, D. V. Chicharro, A. Dorn, M. Grieser, F. Grussie, H. Kreckel, O. Novotny, F. Trost, A. Wolf, T. Pfeifer, C. D. Schröter

Physics Faculty Research & Creative Works

We have momentum-analyzed electrons and recoil ions in triple coincidence with projectiles neutralized in 300-keV Si-+Ar collisions. The experiment was performed at a cryogenic ion storage ring with an in-ring reaction microscope. Differential momentum distributions for detachment with simultaneous target ionization were obtained. At more than 15% of the detachment-only rate the ionization rate is surprisingly large. A correlated two-electron channel is found to be dominant. This is also unexpected because the projectile energy is well below the threshold for the correlated process.

Laser–Assisted Free–Free (Laff) Electron Scattering: An Elastic Angular Distribution In Argon And The Use Of A Novel Pulsed-Laser Multipass System In Laff Experiments, Charles M. Weaver

Theses and Dissertations--Physics and Astronomy

Laser–assisted free–free experiments investigate the emission or absorption of photons when an electron scatters from an atom in the presence of a laser field.

We measured the relative differential cross sections for 350 eV electrons scattered by an argon target in the presence of 1.17 eV photons from a Nd:YAG laser. The angular distribution for elastically scattered 350 eV electrons was measured over scattering angles from 4◦ to 80◦. This distribution exhibits a pronounced maximum near 47◦ and is symmetric about this angle, as predicted by a Kroll–Watson approximation (KWA) calculation for the experimental kinematics. These measurements directly test a …

A Distorted-Wave Approach To The Elastic Scattering Of Twisted Electrons, Allison Harris, Stephan Fritzsche

Faculty publications – Physics

The elastic scattering of spinless vortex electrons on realistic target atoms has been investigated. In particular, expressions are derived in different approximations for the angular distribution of elastically scattered electrons. We develop a distorted wave formalism that includes the effect of the atomic potential on the impinging vortex electron and compare this to a plane-wave Born approximation (PWBA) without such a distortion. Detailed computations have been performed for elastic scattering of vortex electrons on helium, neon, and argon targets by varying the energy, topological charge, and opening angle. Our results show that the overall magnitude of the angular distribution of …

Entangled Photoelectron Attosecond Spectroscopy, Jonathan Sar-Shalom

Honors Undergraduate Theses

In this thesis we propose an interferometric scheme to retrieve the dynamics of an electron wave packet emitted from two distinct residual photo-ion channels in the ionization of an atom by an ultra-short UV pulse. EPAS (Entangled-Photoelectron Attosecond Spectroscopy) works by having a non-overlapping UV and few-cycle IR pulse, where the IR is tuned near the transition frequency between two electronic bound states of the photo-ion. Using a time-dependent simulation based on a two-channel atomic model, supported by a perturbative approach, we were able to compute the resulting interference in the angular distribution of the photoelectron and retrieve the energy-dependent …

Investigation Of Colorimetric Trends In Rare-Earth Co-Doped Ypo₄, Barit K. Essman

All Master's Theses

From detectors in scientific instrumentation to medical imaging devices and nuclear monitoring systems to LEDs seen in consumer products, phosphors are utilized in a myriad of applications experienced by both the general public and scientific community alike. For many phosphor applications, emission color and intensity are notably important features to consider. When phosphors are co-doped with rare-earth activators, the ability to predict emission intensity and color output becomes challenging due to competition kinetics and energy transfer between the dopants. During this study, correlation between trends in co-doped phosphor excitation and color output were analyzed to interpret optical behaviors originating from …