Atomic, Molecular and Optical Physics Commons^™

Experimental Realization Of Supergrowing Fields, Sethuraj K. R., Tathagata Karmakar, S. A. Wadood, Andrew N. Jordan, A. Nick Vamivakas

Mathematics, Physics, and Computer Science Faculty Articles and Research

Supergrowth refers to the local amplitude growth rate of a signal being faster than its fastest Fourier mode. In contrast, superoscillation pertains to the variation of the phase. Compared to the latter, supergrowth can have exponentially higher intensities and promises improvement over superoscillation-based superresolution imaging. Here, we demonstrate the experimental synthesis of controlled supergrowing fields with a maximum growth rate of ∼19.07 times the system bandlimit. Our work is an essential step toward realizing supergrowth-based far-field superresolution imaging.

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM Month

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …

Three-Wave Mixing Experiments In Indium–Tin–Oxide Thin-Films With No Phase Matching, Kyle Wynne, Marjan Bazian, Mark C. Harrison

Engineering Faculty Articles and Research

One challenge of using nonlinear optical phenomena for practical applications is the need to perform phase-matching. Recently, epsilon-near-zero materials have been shown to demonstrate strong optical nonlinearities, in addition to their other unique properties. As suggested by their name, the permittivity of the material is close to zero for a certain wavelength range. We demonstrate that this small permittivity allows for efficient three-wave mixing interactions to take place in indium–tin–oxide thin films without the need for phase matching the pump and signal beams. The efficiency of the second-order nonlinear interactions is characterized, and cascaded three-wave mixing is demonstrated.

Proton And Neutron As Coaxial Structures, Polievkt Perov

College of Arts & Sciences Faculty Works

We suggest that a proton and a neutron are coaxial spinning structures. It is assumed that an up-quark and a down-quark composing a proton and a neutron each contain three like charges revolving about the axis where one (in the up-quark) or two (in the down-quark) basic fractional charges reside. In the case of particles with more than one charge on the axis of rotation, for example in a down-quark, the distance between the charges on the axis is determined by the requirement of zero net force on each charge on the axis. In a proton, two up-quark and one …

Measuring The Density Of Ultracold Rydberg Atoms, Chakradhar Pulipaka, Philip Conte, Aidan Kirk

Physics and Astronomy Summer Fellows

The energy exchange between ultracold, highly-excited, or Rydberg, atoms can be used to model quantum mechanical systems. When interpreting the results of these systems, it is important to know the density of the Rydberg atoms. In a recent experiment, we have studied several clusters of states that form a nearly harmonic ladder of clusters. The Rydberg atoms all start in one energy cluster, and the interactions between them allows energy to spread to all the other states. We have developed new analysis software along with a method in which a simple four-level system can calibrate the density for our experiment. …

Exploration Of Semiconductor Gain Medium, Resonator, Pump, And Frequency Stabilization For Laser Guide Star Applications, Mingyang Zhang

Optical Science and Engineering ETDs

Laser Guide Star (LGS) systems are essential for adaptive optics in ground-based astronomical observation. This dissertation demonstrates the feasibility of semiconductor-based LGS systems using the membrane external-cavity surface-emitting laser (MECSEL) platform, employing multiple quantum wells. Various laser cavity configurations were analyzed through simulations and experiments. The in-well pumping method was explored to reduce the quantum defect and address thermal limitations. Multi-pass pumping schemes were designed with Zemax modeling and demonstrated experimentally. To simplify multi-pass pumping, the hybrid-MECSEL (H-MECSEL) design was introduced. COMSOL modeling studied thermal management and thermal lensing effect.

The H-MECSEL achieved approximately 30 W of output power at …

Twist-Assisted All-Antiferromagnetic Tunnel Junction In The Atomic Limit, Yullang Chen, Kartik Samanta, Naafls A. Shahed, Haojle Zhang, Chi Fang, Arthur Ernst, Evgeny Y. Tsymbal, Stuart S.P. Parkin

Nebraska Center for Materials and Nanoscience: Faculty Publications

Antiferromagnetic spintronics^1,2 shows great potential for high-density and ultrafast information devices. Magnetic tunnel junctions (MTJs), a key spintronic memory component that are typically formed from ferromagnetic materials, have seen rapid developments very recently using antiferromagnetic materials3,4. Here we demonstrate a twisting strategy for constructing all-antiferromagnetic tunnel junctions down to the atomic limit. By twisting two bilayers of CrSBr, a 2D antiferromagnet (AFM), a more than 700% nonvolatile tunnelling magnetoresistance (TMR) ratio is shown at zero field (ZF) with the entire twisted stack acting as the tunnel barrier. This is determined by twisting two CrSBr monolayers for which the TMR …

Human Second Metacarpal Nanocrystal Analysis, William Abramovich

DePaul Discoveries

Female human bones dated to the 6^th - 8^th century CE were uncovered in Greding Germany after archaeologists discovered a medieval cemetery. Age-at-death estimates have been determined, and data from several techniques are currently being analyzed to learn more about these samples. The purpose of this project is to study the diaphyses of the second metacarpal (mc2) bones excavated using wide-angle x-ray scattering data collected at beamline 1-ID of the Advanced Photon Source at Argonne National Laboratory. The diffraction data were refined using the Rietveld method to obtain lattice (‘a’ and ‘c’) parameter values …

Design Of Long-Distance Entanglement Distribution Protocols For Quantum Networks, Stav Haldar

LSU Doctoral Dissertations

Future quantum technologies such as quantum communication, quantum sensing, and distributed quantum computation, will rely on networks of shared entanglement between spatially separated nodes. Distributing entanglement between these nodes, especially over long distances, currently remains a challenge, due to limitations resulting from the fragility of quantum systems, such as photon losses, non-ideal measurements, and quantum memories with short coherence times. In the absence of full-scale fault-tolerant quantum error correction, which can in principle overcome these limitations, we should understand the extent to which we can circumvent these limitations. In this work, we provide improved protocols and policies for entanglement distribution …

Testing Of An Organic Metal Halide Perovskite For Fast Neutron Detection, Wyatt Panaccione, Zhifang Shi, Praneeth Kandlakunta, Taylor M. Nichols, Susan White, Jinsong Huang, Lei R. Cao

Student Publications

In this work, we synthesized and characterized the Methylhydrazinium Lead Trichloride MHyPbCl₃(CH₃NH₂NH₂PbCl₃) perovskite as a fast neutron detector. The high hydrogen density of MHyPbCl3 enables efficient energy conversion from a fast neutron into a recoiled proton through the 1H(n,n)1H elastic scattering interaction, thereby, allowing for direct charge detection. Through IV characterization and X-Ray excitation, the crystal demonstrated a high resistivity at 4.43E11 ω cm and a good mobility-lifetime product (μτ) of 9.1E-3 ^cm2/_V respectively, under C₆₀/BCP/Cu and Au contact configuration to form an ohmic-ohmic …

Diffuse Reflectance Spectroscopy For Optical Characterizations Of Orthotopic Head And Neck Cancer Models In Vivo, Pranto Soumik Saha, Jing Yan, Caigang Zhu

Markey Cancer Center Faculty Publications

We demonstrated an easy-to-build, portable diffuse reflectance spectroscopy device along with a Monte Carlo inverse model to quantify tissue absorption and scattering-based parameters of orthotopic head and neck cancer models in vivo. Both tissue-mimicking phantom studies and animal studies were conducted to verify the optical spectroscopy system and Monte Carlo inverse model for the accurate extraction of tissue optical properties. For the first time, we reported the tissue absorption and scattering coefficients of mouse normal tongue tissues and tongue tumor tissues. Our in vivo animal studies showed reduced total hemoglobin concentration, lower tissue vascular oxygen saturation, and increased tissue scattering …

Generating Bessel Beams With An Elastomeric Replica Of A Weevil Carapace, Paz Victoria T. Ramos, Michie Vianca D. De Vera, Raphael Guerrero

Physics Faculty Publications

We generate a zero-order Bessel beam with a laser beam focused onto an elastomeric replica of a weevil carapace scale. Carapace surface structures are imprinted on an elastomeric cast via soft lithography. The output Bessel beam exhibits the expected properties of non-diffraction over a propagation range of 30 cm. The width of the central spot at a propagation distance of 25 cm is 296:8 μm, corresponding to a replicated weevil scale with a diameter of 64.3 μm acting as an annular slit. Self-healing of the beam after encountering a wire obstruction is also observed.

Coherent Backscattering Under Conditions Of Electromagnetically Induced Transparency In Ultracold Rubidium, Joshua D. Carter

Physics Theses & Dissertations

This dissertation presents experimental results of coherent backscattering of light in an ultracold ensemble of rubidium atoms confined in a magneto optical trap under conditions of electromagnetically induced transparency (EIT) in a cascade-type system. Electromagnetically induced transparency was investigated experimentally in both a counterpropagating and orthogonal laser geometry and compared to theory. The experimental results were largely in good agreement with theory. Coherent backscattering was then measured with and without an EIT control field present to investigate the modification, if any, that EIT has on the enhancement of the coherent backscattering cone. The results indicated that the electromagnetically induced transparency …

Investigation Of Cooperative Subradiance In Dense Ultracold Rubidium Ensembles, Brent Michael Jones

Physics Theses & Dissertations

This dissertation presents results of an experimental investigation of the time resolved fluorescence from a cold and dense ensemble of ⁸⁷Rb atoms after the sample is illuminated by a short probe pulse. The goal of the experiment was to investigate cooperative subradiant behavior, characterized by a much longer decay time compared to the natural lifetime, induced in an off resonant probe regime. Such long lived states, if controllable, would provide a means to store quantum information. The samples were initially created in a magnetooptical trap before atoms were loaded into a far off resonance trap to achieve atomic densities …

Accelerator Based Techniques Iba To Characterize Archeological Artefacts: Case Study Of Ancient Ceramics, Ahmad Reslan, Mohamad Roumie, Sandrine Elaigne, Bilal Nsouli, Mahmoud Korek

BAU Journal - Science and Technology

Ion beam analysis techniques IBA, in particular proton induced X-ray emission PIXE, play an effective and efficient role in the characterization of cultural heritage objects. As early as the 1970s, PIXE technique was applied as reliable analytical technique to determine the elemental composition of archeological artefacts, where many accelerator laboratories worldwide are still involved in such applications. It has the advantage to be multi-elemental (Na to Pb) with major, minor and trace element analysis down to part per million or ppm, fast (few minutes per sample), non-destructive and its possible combination with other IBA techniques that can reveal other information. …

Defect-Free Nanowelding Of Bilayer Snse Nanoplates, Jing-Rong Ji, John W. D. Villanova, Salvador Barraza-Lopez, Stuart S. P. Parkin, Kai Chang

Physics Faculty Publications and Presentations

Nanowelding is a bottom-up technique to create custom-designed nanostructures and devices beyond the precision of lithographic methods. Here, a new technique is reported based on anisotropic lubricity at the van der Waals interface between monolayer and bilayer SnSe nanoplates and a graphene substrate to achieve precise control of the crystal orientation and the interface during the welding process. As-grown SnSe monolayer and bilayer nanoplates are commensurate with graphene's armchair direction but lack commensuration along graphene's zigzag direction, resulting in a reduced friction along that direction and a rail-like, 1D movement that permits joining nanoplates with high precision. This way, molecular …

Pt-Symmetry And Eigenmodes, Tamara Gratcheva

University Honors Theses

Spectra of systems with balanced gain and loss, described by Hamiltonians with parity and time-reversal (PT) symmetry is a rich area of research. This work studies by means of numerical techniques, how eigenvalues and eigenfunctions of a Schrodinger operator change as a gain-loss parameter changes. Two cases on a disk with zero boundary conditions are considered. In the first case, within the enclosing disk, we place a parity (P) symmetric configuration of three smaller disks containing gain and loss media, which does not have PT-symmetry. In the second case, we study a PT-symmetric configuration …

Phase Error Scaling Law In Two-Wavelength Adaptive Optics, Milo W. Hyde Iv, Matthew Kalensky, Michael J. Spencer

Faculty Publications

We derive a simple, physical, closed-form expression for the optical-path difference (OPD) of a two-wavelength adaptive-optics (AO) system. Starting from Hogge and Butts’ classic OPD variance integral expression, we apply Mellin transform techniques to obtain series and asymptotic solutions to the integral. For realistic two-wavelength AO systems, the former converges slowly and has limited utility. The latter, on the other hand, is a simple formula in terms of the separation between the AO sensing (i.e., the beacon) and compensation (or observation) wavelengths. We validate this formula by comparing it to the OPD variances obtained from the aforementioned series and direct …

Simulation Of Linear And Cyclic Alkanes With Second-Order Møller–Plesset Perturbation Theory Through Adaptive Force Matching, Alexei Nikitin, Feng Wang

Chemistry & Biochemistry Faculty Publications and Presentations

Predicting ensemble properties, such as density and heat of vaporization, of small hydrocarbons is challenging due to the dispersion-dominated weak interactions between these molecules. With the adaptive force matching (AFM) method, the bonded and short-range nonbonded interactions are fitted to second-order Møller–Plesset perturbation theory (MP2) references computed with the def2-TZVP basis set. The dispersion is modeled using symmetry adapted perturbation theory (SAPT) at MP4 accuracy using the def2-TZVPD basis set. A new charge matrix decomposition technique is described to obtain partial charges in AFM. Although the models developed do not have any empirical parameters, several properties of the resulting models …

Collisional Broadening And Shift Of Rubidium 42D5/2 → N2F Line Shapes With Helium And Electrons, Dillon T. Nice

Theses and Dissertations

Line shapes for three rubidium 4²D_5/2 → n²F transitions were collected using pump probe spectroscopy. Broadening rates for Rb-He collisions ranged from 139–171 MHz/Torr and shift rates ranged from 113–146 MHz/Torr. Then, line shapes were collected at different alkali densities to measure electron density. Electron density had a clear “runaway ionization density threshold” around 1.5×10¹³ cm⁻³. The three transitions agreed within 2% on the observed fractional ionization when calculated using the observed Stark width but did not agree on the observed fractional ionization when calculated using the observed Stark shift. These results …

A Computational Investigation Of Wood Selection For Acoustic Guitar, Jonah Osterhus

Senior Honors Theses

The acoustic guitar is a stringed instrument, often made of wood, that transduces vibrational energy of steel strings into coupled vibrations of the wood and acoustic pressure waves in the air. Variations in wood selection and instrument geometry have been shown to affect the timbre of the acoustic guitar. Computational methods were utilized to investigate the impact of material properties on acoustic performance. Sitka spruce was deemed the most suitable wood for guitar soundboards due to its acoustic characteristics, strength, and uniform aesthetic. Mahogany was deemed to be the best wood for the back and sides of the guitar body …

Effects Of Post-Deposition Annealing On Room Temperature Deposited Zinc Oxide, Ishan Rayen

Macalester Journal of Physics and Astronomy

This study focuses on thin film deposition of ZnO onto a glass slide using magnetron sputtering. The focus of the study is to understand the effects of post-deposition annealing temperatures. The goal is to optimize crystal quality, conductivity, and transparency. The results attempt to answer the effects of room temperature deposition and changes in film properties once annealed. Annealing temperatures ranged from 100°C to 400°C with an annealing time of 30 minutes. This found an ideal temperature of 250°C for post-deposition annealing, resulting in approximately 3.86 times more conductivity with little to no decrease in transparency. However crystal quality did …

Optical Transport Of Ultracold Atoms, David Vera

Undergraduate Honors Theses

At temperatures near absolute zero, bosons form a macroscopic quantum state that can be manipulated and imaged in a very controlled and tunable way. To reach these extreme temperatures near absolute zero, advanced methods in cooling, including laser and evaporative cooling, must be used. In addition to these techniques for cooling, atoms must also be held up against the constant pull of gravity, so additional trapping techniques using lasers and magnets are used. In our lab at University of San Diego, we are implementing a tunable lens system (TLS) to optically transfer atoms to a more optically accessible location. A …

Entanglement With Neutral Atoms In The Simulation Of Nonequilibrium Dynamics Of One-Dimensional Spin Models, Anupam Mitra

Physics & Astronomy ETDs

Quantum entanglement is a key ingredient for quantum information processing with capabilities beyond that of classical computation. We study the generation and role of entanglement in the dynamics of spin-1/2 models, both for the design of quantum gates for general-purpose quantum computation and for quantum simulation of interacting spin models. We introduce the neutral atom Mølmer-Sørensen gate, involving rapid adiabatic Rydberg dressing interleaved in a spin-echo sequence. We show its robustness to quasi-static experimental imperfections and favorable scaling with the time-energy scales of Rydberg-mediated entanglement generation. In quantum simulation, we consider critical behavior in quench dynamics of transverse field Ising …

The Rubidium Magneto-Optical Trap: Designing A Robust System For Measurement & Control, Thomas Melody

Honors Program Theses and Projects

This thesis is a culmination of our efforts to construct a robust and flexible opto-mechanical system to fully deliver and control all of the parameters related to the required laser wavelength, polarization, power, beam size, and directionality for both the pump and the re-pump laser beams, delivered from two different lasers, necessary for neutral-atom laser trapping and cooling. This is an extension of the neutral Rubidium Magneto-Optical Trap (MOT) at BSU which afford a macroscopic scale collection of cold atoms where the effective governing laws of physics are quantum in nature rather than classical. My predecessors had done work on …

The Ring-Closing Reaction Of Cyclopentadiene Probed With Ultrafast X‑Ray Scattering, Lisa Huang, Lauren Bertram, Lingyu Ma, Nathan Goff, Stuart W. Crane, Asami Odate, Thomas Northey, Andrés Moreno Carrascosa, Mats Simmermacher, Sri Bhavya Muvva, Joseph D. Geiser, Matthew J. Lueckheide, Zane Phelps, Mengning Liang, Xinxin Cheng, Ruaridh Forbes, Joseph S. Robinson, Matthew J. Hayes, Felix Allum, Alice E. Green, Kenneth Lopata, Artem Rudenko, Thomas J. A. Wolf, Martin Centurion, Daniel Rolles, Michael P. Minitti, Adam Kirrander, Peter M. Weber

Martin Centurion Publications

The dynamics of cyclopentadiene (CP) following optical excitation at 243 nm was investigated by time-resolved pump−probe X-ray scattering using 16.2 keV X-rays at the Linac Coherent Light Source (LCLS). We present the first ultrafast structural evidence that the reaction leads directly to the formation of bicyclo[2.1.0]pentene (BP), a strained molecule with three- and four-membered rings. The bicyclic compound decays via a thermal backreaction to the vibrationally hot CP with a time constant of 21 ± 3 ps. A minor channel leads to ring-opened structures on a subpicosecond time scale.

Nonlinear Rogue Wave Generation For All-Optical Switching In Optical Fibers And Photonic Integrated Circuits, Samuel Alexander Bechtold

Honors Program Theses and Projects

For my thesis we discuss the history of optics, electronics and photonicsproviding a framework from which I investigate the viability of engineering a Photonic Integrated Circuit (PIC) that takes advantage of the nonlinear optical process known as Rogue Wave Generation (RWG) for an all-optical switching mechanism that is capable of switching speeds in the Peta-Hertz (PHz) frequency regime. This topic is introduced through a discussion of how technological advances such as the transistor, laser and optical fiber made modern computing and telecommunications possible. This is followed by a theoretical explanation of the nonlinear optical phenomena known as supercontinuum generation (SCG) …

Spin Disorder Control Of Topological Spin Texture, Hongrui Zhang, Yu-Tsun Shao, Xiang Chen, Binhua Zhang, Tianye Wang, Fanhao Meng, Kun Xu, Peter Meisenheimer, Xianzhe Chen, Xiaoxi Huang, Piush Behera, Sajid Husain, Tiancong Zhu, Hao Pan, Yanli Jia, Nick Settineri, Nathan Giles-Donovan, Zehao He, Andreas Scholl, Alpha N'Diaye, Padraic Shafer, Archana Raja, Changsong Xu, Lane W. Martin, Michael F. Crommie, Jie Yao, Ziqiang Qiu, Arun Majumdar, Laurent Bellaiche, David A. Muller, Robert J. Birgeneau, Ramamoorthy Ramesh

Physics Faculty Publications and Presentations

Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe₃GaTe₂, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights …

Algorithm-Based Linearly Graded Compositions Of Gesn On Gaas (001) Via Molecular Beam Epitaxy, Calbi Gunder, Mohammad Zamani-Alavijeh, Emmanuel Wangila, Fernando Maia De Oliveira, Aida Sheibani, Serhii Kryvyi, Paul C. Attwood, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo

Physics Faculty Publications and Presentations

The growth of high-composition GeSn films in the future will likely be guided by algorithms. In this study, we show how a logarithmic-based algorithm can be used to obtain high-quality GeSn compositions up to 16% on GaAs (001) substrates via molecular beam epitaxy. Herein, we use composition targeting and logarithmic Sn cell temperature control to achieve linearly graded pseudomorph Ge_1−xSn_x compositions up to 10% before partial relaxation of the structure and a continued gradient up to 16% GeSn. In this report, we use X-ray diffraction, simulation, secondary ion mass spectrometry, and atomic force microscopy to analyze and …

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 …