Atomic, Molecular and Optical Physics Commons^™

A Study On The Great Comet Of 2024: C/2023 A3 (Tsuchinshan–Atlas) Via Radio Interferometry, Jesse Bier, Nathan X. Roth

Undergraduate Research Symposium

Our solar system is approximately 4.5 billion years old. Comets are remnants of its formation, serving as time capsules to give us an understanding of its natal heritage. Revealing our own solar system’s history allows us to gain insights into other young stellar systems and the potential for life elsewhere. C/2023 A3 (Tsuchinshan–ATLAS) was a comet from the Oort cloud on its first and possibly only journey to the inner solar system. The comet grew in brightness until it was brighter than Venus on October 9^th, 2024, making it temporarily brighter than Venus and one of the brightest …

Improving The Electrochemical Properties Of Mno2 By Doping With Fe For Water Splitting And Supercapacitor Application, Joseph Okwe

Electronic Theses & Dissertations

An Abstract of the Thesis by

Joseph Okwe

These days when the issue of energy is talked about, it is usually more than just the usefulness of different types of energy. This topic now encompasses ways of generating and storing energy in the most efficient and sustainable way. For this reason, various research has shown that materials that are fabricated for the purpose of energy storage and conversion also find applications in other areas such as water splitting and supercapacitors. And so certain materials, when synthesized, can serve more than one purpose in either generating or storing energy. This project …

The Study Of Hybrid Nanostructures For Optoelectronics, Alex Davis, Khaoula Dehhou

Publications and Research

Hybrid nanostructures that combine zero-dimensional (0D) quantum dots (QDs) with two-dimensional (2D) transition-metal dichalcogenides (TMDs) are promising building blocks for next-generation optoelectronic devices, such as highly sensitive photodetectors, light-emitting diodes, and tunable light sources. These hybrid systems take advantage of the strong, size-dependent emission of colloidal QDs and the high carrier mobility and tunable band structure of 2D materials. In this research, we investigate hybrid structures composed of colloidal CdSe/ZnS, CuInS/ZnS, and PbS QDs integrated with indium selenide (InSe), a TMD known for its exceptional electron mobility and robust photoluminescence in few-layer form. The goal is to understand how interfacial …

Time-Resolved 3d Momentum Spectroscopy In Continuous Wave Atomic Photoionization Experiments, K. L. Romans, B. P. Acharya, A. H.N.C.De Silva, K. Foster, O. Russ, Daniel Fischer

Physics Faculty Research & Creative Works

An experimental continuous-wave (cw) pump-probe scheme is demonstrated by investigating the population and photoionization dynamics of an atomic system. In particular, 6Li atoms are initially prepared in optically pumped 22S1/2 and 22P3/2 states before being excited via multi-photon absorption from a tunable femtosecond laser. The subsequent cascade back to the ground state is analyzed by ionizing the atoms in the field of a cw optical dipole trap laser. Conventional spectroscopic methods, such as standard cold-target recoil ion momentum spectroscopy or velocity map imaging, cannot provide simultaneous momentum and time-resolved information on an event-by-event basis for the system investigated here. The …

Investigation Of Laser Based Flow Diagnostics With Metastable Argon, Sterling S. Gordon

Physics Theses & Dissertations

The overarching motivation of this work is the development of seedless, non-intrusive, laser-based diagnostics for supersonic airflow in wind tunnels. To advance this goal, this dissertation fo-cuses on three-photon excitation in a research-grade argon beam within a tabletop vacuum system, which offers a controlled environment for testing and refining the approach. The chosen excitation scheme drives argon atoms to the 3d[5/2]₃ state using a pulsed Ti:Sapphire laser system, enabling time-of-flight (ToF) measurements on atoms that subsequently undergo a multi-step decay to the metastable 4s[3/2]₂ state. Although full realization of this excitation scheme was hindered by technical …

Fish-Spec: Fast Identification System For Handheld Spectroscopy And Species Classification, Mitchell Sueker, Nicholas Mackinnon, Gregory Bearman, Amanda Tabb, Diane Kim, Rosalee S. Hellberg, Alireza Akhbardeh, Hamid Reza Marateb, Jianwei Qin, Moon Kim, Fartash Vasefi, Hossein Kashani Zadeh

Food Science Faculty Articles and Research

Accurate fish species identification is critical to prevent mislabeling and fraud in the seafood industry. We present a handheld multi-mode point spectroscopy system that combines fluorescence (365 and 395 nm excitation) and reflectance measurements in the visible to near-infrared (∼350–900 nm) and short-wave infrared (∼900–1700 nm) regions for rapid, non-destructive classification of fish fillets. Tissue spectra were acquired at 25 positions on 68 fillets from 11 species, in both frozen and thawed states. Feature-level fusion across all four modes enabled higher classification accuracy than any single mode alone. A global machine-learning model classified all species with 85 ± 2.8 %, …

Parameterizing Ion–Lipid Interactions From Local Clusters To Reproduce Experimental Bulk Properties Of Lipid Bilayers, W. Matthew Saunders

USF Tampa Graduate Theses and Dissertations

Phospholipids are the main component of cell membranes, providing a delimiting boundary for cells from their environments or from their organelles from the cytosol. Thiscompartmentalization allows cells to maintain quite different solutions within their cells and organelles, including different mixtures dissolved ions. Consequently, these membranes are constantly flanked by complex mixtures of salts at varied concentrations. To study membrane structure, one cannot neglect the contribution of the salts in the local solution. Ions perturb bilayer structure via specific interaction with the phospholipids, primarily with the headgroups. Experimental studies of these systems are somewhat at odds — scattering experiments with different …

Electric-Field Tunable Magnetoexcitons In Xenes/Hbn/Tmdc, Xenes/Hbn/Bp, And Xenes/Hbn/Tmtc Heterostructures, Roman Ya. Kezerashvili, Anastasia Spiridonova, Klaus Ziegler

Publications and Research

In this work, we propose novel van der Waals heterostructures composed of Xenes, transition metal dichalcogenides (TMDCs), phosphor ene, and transition metal trichalcogenides (TMTCs), which are separated by insulating hexagonal boron nitride (hBN) layers. We theoreti cally investigate the behavior of Rydberg indirect excitons in Xenes/hBN/TMDC, Xenes/hBN/phosphorene and Xenes/hBN/TMTC heterostructures subjected to parallel external electric and magnetic fields that are oriented perpendicular to the layers. By incorporating both isotropic and anisotropic materials, we demonstrate that excitonic properties can be effectively tuned through the external field strengths and the heterostructure design. Our results show that the exciton reduced mass and the …

Intrinsic Defects (Vacancies And Antisites) In Neutron Irradiated Cdsip2 Crystals, Timothy D. Gustafson, Elizabeth M. Scherrer, Nancy C. Giles, Kevin T. Zawilski, Peter G. Schunemann, Jonathan E. Slagle, Kent L. Averett, Larry E. Halliburton

Faculty Publications

Cadmium silicon phosphide (CdSiP₂) is a nonlinear optical material widely used in optical parametric oscillators. Intrinsic defects (vacancies and antisites) are responsible for unwanted broad optical absorption bands in these crystals that degrade the performance of the devices. In the present work, optical absorption and electron paramagnetic resonance (EPR) spectra are acquired (at room temperature and 12 K, respectively) from a neutron-irradiated CdSiP₂ crystal. After the irradiation, the crystal is highly absorbing from the band edge near 600 nm to beyond 1.3 μm because of overlapping defect-related absorption bands. Heating to 550 °C removes nearly all the …

Coupled-Channel Calculations Of Fully Differential Cross Sections For Ionization In 75-Kev P + He Collisions, K. H. Spicer, N. W. Antonio, M. S. Schöffler, Michael Schulz, A. S. Kadyrov

Physics Faculty Research & Creative Works

The fully differential cross section is the most detailed quantity that can be measured or calculated to study ionization in few-body systems. For 75 keV proton collisions with helium, various experimental data are available. However, previous theoretical calculations found significant discrepancies across the entire range of data. In this work the wave-packet convergent close-coupling method is extended to calculating these cross sections for electrons ejected with energies from 1 to 75.4 eV. The approach utilizes a two-center expansion and correlated two-electron helium wave functions to describe the four-body proton-helium system. While there is good agreement with the experiment for electrons …

Multiply Differential Study Of Detachment With Simultaneous Target Excitation In Anion-Atom Collisions, M. Schulz, F. Herrmann, W. Zhang, 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 measured momenta of electrons and recoil ions in triple coincidence with neutralized projectiles for slow collisions between various anions and target atoms. From the data we extracted triple differential momentum and angular distributions of electrons ejected in detachment, in detachment with simultaneous target ionization (DI), and in detachment with simultaneous target excitation (DE). The DI rates relative to the DE rates depend sensitively on the projectile speed and on the properties of the target.

Continuous Pump-Probe Experiment To Observe Zeeman Wave-Packet Dynamics, K. L. Romans, K. Foster, S. Majumdar, B. P. Acharya, O. Russ, A. H.N.C. De Silva, Daniel Fischer

Physics Faculty Research & Creative Works

In this work, we study the coherent dynamics of an atomic Zeeman wave packet using a continuous pump-probe scheme. A polarized Zeeman wave packet is created in laser-cooled lithium atoms via few-photon excitation by a femtosecond laser pulse, producing a state with a magnetic moment tilted relative to an external magnetic field. The subsequent Larmor precession of the atomic magnetic moment is probed via continuous ionization by an optical dipole trap (ODT) laser. The resulting ionization fragments—photoelectrons and photo ions—are detected in coincidence using a cold target recoil ion momentum spectrometer (COLTRIMS). While the ODT facilitates further cooling of the …

Single-Molecule Orientation And Localization Microscopy, Sophie Brasselet, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Single-molecule localization microscopy (SMLM) offers enhanced spatial resolution in optical microscopy, providing detailed insights into the spatial organization of proteins in cells at the nanoscale. Over the past decade, SMLM has progressively incorporated the capability to retrieve the orientations of single molecules using their polarized dipolar emission pattern. Here we explore recent advancements in single-molecule orientation and localization microscopy (SMOLM), which yields super-resolved images of molecular three-dimensional (3D) orientations, wobble and 3D positions. This advancement opens possibilities to explore the nanoscale organization and conformation of biological molecules as well as to monitor and design local 3D optical fields in nanophotonics. …

Electrical Characterization Of Germanium Tin Alloys And Devices For Space Reliability, Kevin K. Choe

Theses and Dissertations

GeSn (germanium tin) alloys are potentially well suited for near-mid infrared space optoelectronic applications. Alloys of GeSn have similar properties to group III-V and mercury-cadmium-telluride semiconductors and are compatible with cost-effective complementary metal oxide semiconductor (CMOS) manufacturing technology. Recent progress in non-equilibrium remote plasma-enhanced chemical vapor deposition (RPECVD) has enabled the crystalline growth of GeSn with Sn concentrations of up to 10% without Sn surface segregation. Several experimental studies in previous literature report CVD- or molecular beam epitaxy (MBE)-grown GeSn alloys achieving a direct bandgap with 6%-9% Sn content. This novel growth technique opens opportunities for a cost-effective, next-generation optical …

Simulating Chemiluminescence Spectra Of Oh Radical Using Quantum Dynamical Simulations, Triet M. Cao

Research from the Berry Summer Thesis Institute, 2025

Chemiluminescence is a phenomenon of light emission that occurs when molecules transition from an excited state to the ground state. This phenomenon is widely utilized in applications ranging from quantifying product yields in chemical reactions to biological imaging and atmospheric chemistry studies. It has also been used in many crucial applications in the scarce conditions of heat and electricity, such as light sources for astronomy discovery or deep-sea diving. A notable example of such reactions is combustion, where highly reactive hydroxyl radicals (OH) are products. These radicals exhibit a chemiluminescence spectrum because of the interaction between their ground state and …

The Effects Of I-127 On A High-Granularity Lii(Eu) Bonner Sphere Spectrometer Response Matrix, Adam Card, Andrew W. Decker

Student Publications

The measurement of neutron energy spectra using a Bonner Sphere Spectrometer (BSS) requires spectrum unfolding. One necessary component of spectrum unfolding is an accurate neutron response matrix, which describes the energy shift experienced by neutrons when passing through different moderation configurations prior to detection. Leveraging the recently-released ENDF/B-VIII.0 cross-section library, this work details the development of a new LiI(Eu) scintillator response matrix that features improved energy binning granularity as well as increased isotopic and statistical accuracy. Using MCNP6.2, detector responses were modeled at 105 discrete log-equi-spaced incident neutron energies from 1.000 × 10⁻⁹ to 2.512 × 10¹ MeV …

Non-Linear Atom-Laser Interactions Using Rubidium Pump-Probe Spectroscopy, Grace Neil

Beyond: Undergraduate Research Journal

An experiment was performed to demonstrate the pump-probe spectroscopy of Rubidium (Rb) vapor, revealing the nonlinear atom-laser interactions in the 5S1/2 ↔ 5D5/2 transition in Rb that can be used to generate quantum entanglement between two laser beams. The setup included a tunable infrared diode laser, optical mirrors, photodiode-detectors, a beam-splitter, and a temperature- regulated rubidium gas chamber, all of which are controlled by the TeachSpin laser controller and monitor. The output from the laser-diode was split into a pump (90%) and a signal probe (10%), which intersected in counter-propagating directions inside the Rubidium chamber. The analysis shows that in …

Volumetric Imaging Of Cellular Dynamics Using Light-Sheet Microscopy: From Subcellular Structures To Whole Organisms, Md Nasful Huda Prince

Optical Science and Engineering ETDs

Advancing biomedical imaging requires platforms that combine high-resolution, speed, and stability across biological scales. This dissertation presents three innovations designed to address limitations of conventional light-sheet and oblique plane imaging. First, we introduce Reflected Inline Detection in Epi-Oblique Plane Microscopy (RIDE-OPM), a compact and drift-resistant system that eliminates a tertiary detection path while maintaining alignment flexibility, enabling robust long-term live imaging. Second, we present a high-speed Axially Swept Light-Sheet Microscopy (ASLM) platform for cleared tissues, using dual foci and synchronized sweeping to achieve isotropic sub-micron resolution at up to 40 frames-per-second, a fourfold improvement over standard ASLM. Integrated with a …

Phase Nanoscopy With Correlated Frequency Combs, Xiaobing Zhu

Optical Science and Engineering ETDs

In this dissertation a sensing method applying to any physical quantity that modifies optical phase is developed. Two pulses are produced inside a synchronously pumped Optical Parametric Oscillator, generating two identical, undistinguishable frequency combs. The physical quantity to be measured applies a small phase shift/round trip to one of the pulses, resulting in a frequency shift of the corresponding comb. The latter frequency is measured as a beat by interfering the two combs on a detector. A world record resolution, close to the quantum limit, of 0.033 nanoradian (corresponding to 0.006 fm in displacement) is achieved. A detailed analysis of …

Advancing Diamond Quantum Sensors: Isotropic Flux Concentrators And Phase Noise Mitigation, Maziar Saleh Ziabari

Optical Science and Engineering ETDs

Two methods for improving the sensitivity of nitrogen vacancy quantum sensors in diamond are explored. First, by passively concentrating the magnetic flux, three orthogonally oriented ferrite truncated cone pairs amplify the field isotropically by 19 times, allowing measurement of Earth's field without a bias field and increasing sensitivity. Through thorough analysis, modeling and tuning a novel 3-dimensional flux concentrator system, we achieve a fractional standard deviation of less than 1% anisotropy and quantify minimal deadzones and ambient temperature-limited variations below 40 nT/hour. Second, we characterize, model and calculate phase noise in NV experiments, which in NV sensors is effectively indistinguishable …