Atomic, Molecular and Optical Physics Commons^™

Wavefront Sensor Based On Angle Selectivity Of An Optical Filter, Andreas Zepp, Emma Branigan, Julien Garnier, Kevin Murphy, Raphael Bellossi, Karin Stein, Szymon Gladysz

Conference Papers

The effectiveness of free-space laser communications is limited due to wavefront deformations caused by atmospheric optical turbulence. To determine these deformations, we propose a wavefront sensor that utilizes the angular selectivity of an optical transmission filter to measure the first derivative of the wavefront. The transmission filter converts the gradients of the incident wavefront into an intensity distribution. For each direction (x and y) this distribution is captured twice, with different angles between filter and optical axis for each measurement. The contrast of both measurements (calculated for each pixel of the used detector) and the local gradients of the wavefront …

China Spallation Neutron Source And Southern Advance Light Source, Hesheng Chen

Bulletin of Chinese Academy of Sciences (Chinese Version)

China Spallation Neutron Source provides a large multidisciplinary platform for advanced neutron scattering research and application for cutting-edge research in basic science and many fields of the national demands. Its comprehensive performance is in the international advanced level, and has significantly improved the scientific and technological capability and innovation abilities in related fields. The successful construction of China Spallation Neutron Source has greatly promoted the development of the national large science and technology infrastructure in the Guangdong-Hong Kong-Macao Greater Bay Area, and provides important support to the comprehensive national science center in the Greater Bay Area. The synchrotron radiation light …

Exploring The Early Solar System: Cometary Chemical Fingerprints: A Study Of Comet C/2022 E3 (Ztf) Via Near-Infrared Spectroscopy, Grace Puchalski

Undergraduate Research Symposium

Comets are small, icy remnants from the solar system formation (4.5 billion years ago). Their interior composition should reflect the composition and conditions presented in the mid-plane of the protoplanetary region where (and when) they formed. These small objects predominantly reside in two major reservoirs, the Oort cloud and the Kuiper belt. Comets coming from the Oort cloud have long orbital periods while comets from the Kuiper belt have short orbital periods (< 200 years). An overarching goal in astronomy is to understand the conditions presented in the planetary region in the early solar system. Since comets lack a known mechanism of self internal heating, any processes that have changed their composition should only affect a few meters deep, which is believed to be excavated over a course of a perihelion passage into the inner parts of the solar system. As comets get closer to the Sun, solar irradiation causes their ices to sublime, leaving a formation of a freely expanding atmosphere (coma). Depending on the science interest, astrophysicists use different techniques for data collection, a common one being spectroscopy. Using iSHELL spectrograph at the NASA-Near-Infrared Telescope Facility (IRTF), we examine the primary chemical composition (e.g., H2O, CO, CH4, C2H6, C2H2, H2CO, NH3, CH3OH, OCS, and OH) of cometary coma in bright comet C/2022 E3 (ZTF). Our preliminary results indicate the H2O production rate of ~3.4E28 (molecules per second), which corresponds to the rotational temperature of 86 (K). Cometary atmospheres are dense enough that molecules in the inner coma are thermalized by collision (Local Thermodynamic Equilibrium), thus 86 (K) is a physical parameter of coma. We compared the production of the rest of species with that of water (in %) and our results indicated that comet E3 was typical (close to average) in mixing ratios of all volatile species. By mapping the intensity of light with distance from the nucleus,we were able to examine the spatial distribution of volatiles and dust in E3’s coma which were consistent with production directly from the nucleus.

Electromagnetic Theory And Applications, 2nd Edition, Nicholas Madamopoulos, George Kliros

Open Educational Resources

This book intends to provide both the fundamentals of Electromagnetics but also some practical applications of the concepts covered. Having taught electromagnetics for several years, the authors feel that many times the field of electromagnetics comes as “old” and often times students do not appreciate the concepts and their importance in everyday applications. The authors intend to accompany the EM concepts with life applications. Hence, students may see the direct impact of the knowledge they acquire through the study of the field of electromagnetics and better appreciate the field.

Structural, Electronic And Magnetic Properties Of Vanadium Doped Transition Metal Dichalcogenides (Tmds), Qudsia Ashraf

Dissertations, Theses, and Capstone Projects

Magnetic semiconductors are a prerequisite for spintronic devices but their ferromagnetism disappears at room-temperature hindering application in room temperature electronic devices. Enormous research has been conducted on the room-temperature ferromagnetic order in monolayer form of bulk van der Waals materials but the few layer system has not been extensively explored.

Doping is an effective approach to modulate the structural, electronic and magnetic properties of two-dimensional (2D) Transition metal dichalcogenides (TMDs) and expand their application. The effect of vanadium dopant on structural, electronic and magnetic properties of Tungsten Diselenide (WSe₂) was studied by X-ray Photoelectron Spectroscopy (XPS), Atomic Force …

Collisional And Spatial Characterization Of Electron Broadening In Rubidium Vapor, Jordan C. Mindrup

Theses and Dissertations

Stark broadening of the 4²D → 12²F transition of rubidium is examined in a rubidium vapor cell with modulated double pump-probe spectroscopy at helium pressures of 0.001 Torr, 3.0 Torr, and 30.0 Torr. A pressure dependent critical rubidium number density was observed after which the presence of electrons becomes dominant. It is observed that after the rubidium density threshold, a linear relationship is seen between rubidium number density and the Stark broadened width of the line shapes, with a slope of 0.079 ± 0.002, 0.18 ± 0.01, and 0.9 ± 0.1 for helium pressures of 0.001 …

Thermal Phase Fluctuations In Narrow Superfluid Rings, Parth Sabharwal

Dartmouth College Ph.D Dissertations

Remarkable advances have been made in the past decade in the ability to control superfluids in circuit-like configurations. Especially notable are the improvements in the initialization, stabilization and measurement of the circulation of superfluids in geometries with periodic boundary conditions, such as rings. This has significant implications for applications as rotation sensors, magnetometers, and in the emerging field of atomtronics. As the push towards studying supercurrents in lower dimensions and higher aspect ratios continues, in order to realize idealized experimental conditions and explore unusual quantum phases, phase fluctuations become increasingly pronounced, with the potential to destroy long-range order. In this …

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 …

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 …

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.

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 …

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 …

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 …

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 …

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 …

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 …