Topological Insulating States In Photonics And Acoustics,
2019
CUNY Graduate Center
Topological Insulating States In Photonics And Acoustics, Xiang Ni
Dissertations, Theses, and Capstone Projects
Recent surge of interest in topological insulators, insulating in their interior but conducting at the surfaces or interfaces of different domains, has led to the discovery of a variety of new topological states, and their topological invariants are characterized by numerous approaches in the category of topological band theory. The common features shared by topological insulators include, the topological phase transition occurs if the bulk bandgap is formed due to the symmetries reduction, the topological invariants exist characterizing the global properties of the material and inherently robust to disorder and continuous perturbations irrespective of the local details. Most importantly, these …
The Population Densities Of Argon Metastable Levels,
2019
University of San Francisco
The Population Densities Of Argon Metastable Levels, Nada Khogeer, Chelsy Gonzalez, Milka Nikolic
Physics and Astronomy
In this experiment, we used the optical emission spectroscopy (OES) method to obtain the main properties of low temperature Argon plasma. The experiment was sustained in powers and pressures that ranges from 30-100 W and 15-100 mTorr. We used numerical methods for the Argon kinetic model to calculate metastable levels and resonant states for the first excited states in low temperature Argon plasma. By finding the ratio of two spectral lines and finding another ratio from a different upper energy level that goes down to the same two lower energy levels, we can construct a system of two nonlinear equations. …
Single Metalens For Generating Polarization And Phase Singularities Leading To A Reverse Flow Of Energy,
2019
Image Processing Systems Institute оf RAS – Branch of the FSRC “Crystallography and Photonics” RAS, 151 Molodogvardeyskaya St., Samara 443001, Russia
Single Metalens For Generating Polarization And Phase Singularities Leading To A Reverse Flow Of Energy, Victor V. Kotlyar, Anton G. Nalimov, Sergey S. Stafeev, Liam O'Faolain
Cappa Publications
Using Jones matrices and vectors, we show that a metasurface-based optical element composed of a set of subwavelength diffraction gratings, whose anisotropic transmittance is described by a matrix of polarization rotation by angle m, where is the polar angle, generate an mth order azimuthally or radially polarized beam, when illuminated by linearly polarized light, or an optical vortex with topological charge m, when illuminated by circularly polarized light. Such a converter performs a spin–orbit transformation, acting similarly to a liquid-crystal half-wave plate. Using the FDTD-aided numerical simulation, we show that uniform linearly or circularly polarized light passing through the …
Frequency Modulated Hybrid Photonic Crystal Laser By Thermal Tuning,
2019
Cappa Centre, Cork Institute of Technology, Cork, Ireland
Frequency Modulated Hybrid Photonic Crystal Laser By Thermal Tuning, Sharon M. Butler, Andrei P. Bakoz, Praveen K.J. Singaravelu, A. A. Liles, Ben O’Shaughnessy, E. A. Viktorov, Liam O'Faolain, Stephen P. Hegarty
Cappa Publications
We demonstrate frequency modulation (FM) in an external cavity (EC) III-V/silicon laser, comprising a reflective semiconductor optical amplifier (RSOA) and a silicon nitride (SiN) waveguide vertically coupled to a 2D silicon photonic crystal (PhC) cavity. The PhC cavity acts as a tunable narrowband reflector giving wavelength selectivity. The FM was achieved by thermo-optical modulation of the reflector via a p-n junction. Single-mode operation was ensured by the short cavity length, overlapping only one longitudinal laser mode with the reflector. We investigate the effect of reflector modulation theoretically and experimentally and predict a substantial tracking of the resonator by the laser …
Subwavelength Grating-Based Spiral Metalens For Tight Focusing Of Laser Light,
2019
Samara National Research University, 34, Moskovskoye shosse, Samara, 443086, Samara, Russia
Subwavelength Grating-Based Spiral Metalens For Tight Focusing Of Laser Light, Victor V. Kotlyar, Sergey S. Stafeev, Anton G. Nalimov, Liam O'Faolain
Cappa Publications
In this paper, we investigate a 16-sector spiral metalens fabricated on a thin film (130 nm) of amorphous silicon, consisting of a set of subwavelength binary diffractive gratings and with a numerical aperture that is close to unity. The metalens converts linearly polarized incident light into an azimuthally polarized optical vortex and focuses it at a distance approximately equal to the wavelength of the incident light, k ¼ 633 nm. Using a scanning near-field optical microscope, it is shown experimentally that the metalens forms an elliptical focal spot with diameters smaller than the diffraction limit: FWHMx ¼ 0.32k (60.03k) and …
Quartic Metamaterials: The Inverse Method, Perturbations, And Bulk Optical Neutrality,
2019
Georgia Southern University
Quartic Metamaterials: The Inverse Method, Perturbations, And Bulk Optical Neutrality, Thomas Mulkey
Honors College Theses
A primary goal of photonics is designing material structures that support predetermined electromagnetic field distributions. We have developed an inverse method to determine material parameters for a quartic metamaterial from six desired plane waves. This work inspired us to study how perturbations to the parameters can result in optical neutrality.
Investigating The Talbot Effect In Arrays Of Optical Dipole Traps For Neutral Atom Quantum Computing,
2019
California Polytechnic State University, San Luis Obispo
Investigating The Talbot Effect In Arrays Of Optical Dipole Traps For Neutral Atom Quantum Computing, Sergio Aguayo
Physics
Quantum computers are devices that are able to perform calculations not achievable for classical computers. Although there are many methods for creating a quantum computer, using neutral atoms offers the advantage of being stable when compared to other methods. The purpose of this investigation is to explore possible optical dipole trap configurations that would be useful for implementing a quantum computer with neutral atoms. Specifically, we computationally investigate arrays of pinholes, the diffraction pattern generated by them, and the onset of the Talbot effect in these traps. We manipulate the radius of the pinholes, the number of pinholes in the …
Perturbative Generalization Of Nonparaxial Ultrashort Tightly-Focused Elegant Laguerre–Gaussian Beams,
2019
University of Nebraska-Lincoln
Perturbative Generalization Of Nonparaxial Ultrashort Tightly-Focused Elegant Laguerre–Gaussian Beams, Andrew M. Vikartofsky
Department of Physics and Astronomy: Dissertations, Theses, and Student Research
An analytical method for calculating the electromagnetic fields of a nonparaxial elegant Laguerre-Gaussian (eLG) vortex beam is presented for arbitrary pulse duration, spot size, and LG mode. This perturbative approach provides a numerically tractable model for the calculation of arbitrarily high radial and azimuthal LG modes in the nonparaxial regime, without requiring integral representations of the fields. A key feature of this perturbative model is its use of a Poisson-like frequency spectrum, which allows for the proper description of pulses of arbitrarily short duration. The time-domain representation of this model is presented as a non-recursive closed-form expression to any order …
Estimating Coastal Water Turbidity Using Viirs Nighttime Measurement,
2019
University of South Florida
Estimating Coastal Water Turbidity Using Viirs Nighttime Measurement, Chih-Wei Huang
USF Tampa Graduate Theses and Dissertations
Coastal water turbidity is a key environmental factor that influences the relative clarity of the water, which therefore reduces sunlight penetration. The comprehensive spatial and temporal coverage of remote sensing allows mapping of water turbidity near the coast. Even in locations where time-consuming and expensive conventional turbidity monitoring programs exist, local technological limitations prevent complete coverage. Traditional optical satellite techniques using the visible band also have limitations in monitoring turbidity due to non-optimal observing conditions such as clouds, sun-glint, and thick aerosols. In this study, in order to complement the daytime satellite measurements, I used the data from Visible Infrared …
Second-Harmonic Generation From Hyperbolic Plasmonic Nanorod Metamaterial Slab,
2019
University of North Florida
Second-Harmonic Generation From Hyperbolic Plasmonic Nanorod Metamaterial Slab, Gregory Wurtz
Showcase of Faculty Scholarly & Creative Activity
Hyperbolic plasmonic metamaterials provide numerous opportunities for designing unusual linear and nonlinear optical properties. In this work, second-harmonic generation in a hyperbolic metamaterial due to a free-electron nonlinear response of a plasmonic component of the metamaterial is studied. It is shown that owing to a rich modal structure of an anisotropic plasmonic metamaterial slab, the overlap of fundamental and second-harmonic modes results in the broadband enhancement of radiated second-harmonic intensity by up to 2 orders of magnitude for TM- and TE-polarized fundamental light, compared to a smooth Au film under TM-polarised illumination. Compared to the radiated second-harmonic intensity from a …
Optical Detection And Storage Of Entanglement In Plasmonically Coupled Quantum-Dot Qubits,
2019
Argonne National Laboratory
Optical Detection And Storage Of Entanglement In Plasmonically Coupled Quantum-Dot Qubits, M. Otten, S.K. Gray, German Kolmakov V
Publications and Research
Recent proposals and advances in quantum simulations, quantum cryptography, and quantum communications substantially rely on quantum entanglement formation. Contrary to the conventional wisdom that dissipation destroys quantum coherence, coupling with a dissipative environment can also generate entanglement. We consider a system composed of two quantum-dot qubits coupled with a common, damped surface plasmon mode; each quantum dot is also coupled to a separate photonic cavity mode. Cavity quantum electrodynamics calculations show that upon optical excitation by a femtosecond laser pulse, entanglement of the quantum-dot excitons occurs, and the time evolution of the g(2) pair correlation function of the cavity photons …
Tip-Enhanced Nano-Optical Imaging Of Superacid Treated Bilayer Mos2-Ws2 2d Lateral Heterostructures,
2019
University of South Florida
Tip-Enhanced Nano-Optical Imaging Of Superacid Treated Bilayer Mos2-Ws2 2d Lateral Heterostructures, Amala Dixit
USF Tampa Graduate Theses and Dissertations
Nanoscale optical characterization of two-dimensional (2D) materials and heterostructures is important for the design of novel optoelectronic flexible nano-devices. Nano-optical photoluminescence (PL) and Raman imaging of bilayer 2D materials has been a challenging problem due to weak signals. The exciton-dominated light emission of two-dimensional (2D) transition metal dichalcogenide (TMDC) materials is affected by the formation of defects and doping states. Previous studies have shown that chemical treatment modifies the defect and doping states of chemical vapor deposition (CVD)-grown monolayers of MoS2 and WS2, which provides a promising possibility for engineering the optoelectronic properties of these 2D TMDCs. …
The Non-Mechanical Beam Steering Of Light In Reflective Inverse Diffusion,
2019
Air Force Institute of Technology
The Non-Mechanical Beam Steering Of Light In Reflective Inverse Diffusion, Eric K. Nagamine
Theses and Dissertations
Wavefront shaping is a technique that uses spatial light modulators to conjugate the phase of light incident on a rough surface, such that the light will refocus after reflection. This refocusing effect is called reflective inverse diffusion. There currently are two different approaches used to achieve reflective inverse diffusion: iterative methods and matrix methods. Iterative methods find one phase mask which allows for reflected light to be focused at a single, specific position, with results that are immediately available and continuously improving. Matrix methods calculate the complex matrix which describes the rough surface and allows for reflected light to be …
Designing Liquid Crystal For Optoacoustic Detection,
2019
Air Force Institute of Technology
Designing Liquid Crystal For Optoacoustic Detection, Michael T. Dela Cruz
Theses and Dissertations
This research impacts the development of a cost-saving, on-chip device that can replace a wide range of costly, bulky sensors for commercial and defense applications. In particular, the goals of this work were to design and test a sensor that uses the optical properties of liquid crystal (LC) to detect acoustic waves. This began with developing a method to fine-tune the optical features of the liquid crystal. Statistical analysis of select experimental variables, or factors, lead to ideal settings of those variables when creating the sensor. A two-factor and three-factor experiment were separately conducted and analyzed as a preliminary demonstration …
Scaling Film Cooling Adiabatic Effectiveness With Mass Transfer And Thermal Experimental Techniques,
2019
Air Force Institute of Technology
Scaling Film Cooling Adiabatic Effectiveness With Mass Transfer And Thermal Experimental Techniques, Luke J. Mcnamara
Theses and Dissertations
With increasing engine temperatures, it is becoming more important to design effective film cooling schemes. Low temperature, large scale tests are often implemented in the design process to reduce cost and complexity. A nondimensional adiabatic effectiveness can be used as an indication of the performance of a film cooling scheme. However, the coolant flow rate must be properly scaled between the low temperature tests and engine temperatures to accurately predict film cooling effectiveness. This process is complicated by gas property variation with temperature. Tests are commonly conducted using thermal measurement techniques with infrared thermography (IR), but the use of pressure …
A State-Of-The-Art Survey On Deep Learning Theory And Architectures,
2019
University of Dayton
A State-Of-The-Art Survey On Deep Learning Theory And Architectures, Md Zahangir Alom, Tarek M. Taha, Christopher Yakopcic, Stefan Westberg, Paheding Sidike, Mst Shamima Nasrin, Mahmudul Hasan, Brian C. Van Essen, Abdul A. S. Awwal, Vijayan K. Asari
Electrical and Computer Engineering Faculty Publications
In recent years, deep learning has garnered tremendous success in a variety of application domains. This new field of machine learning has been growing rapidly and has been applied to most traditional application domains, as well as some new areas that present more opportunities. Different methods have been proposed based on different categories of learning, including supervised, semi-supervised, and un-supervised learning. Experimental results show state-of-the-art performance using deep learning when compared to traditional machine learning approaches in the fields of image processing, computer vision, speech recognition, machine translation, art, medical imaging, medical information processing, robotics and control, bioinformatics, natural language …
Infrared And Electro-Optical Stereo Vision For Automated Aerial Refueling,
2019
Air Force Institute of Technology
Infrared And Electro-Optical Stereo Vision For Automated Aerial Refueling, William E. Dallmann
Theses and Dissertations
Currently, Unmanned Aerial Vehicles are unsafe to refuel in-flight due to the communication latency between the UAVs ground operator and the UAV. Providing UAVs with an in-flight refueling capability would improve their functionality by extending their flight duration and increasing their flight payload. Our solution to this problem is Automated Aerial Refueling (AAR) using stereo vision from stereo electro-optical and infrared cameras on a refueling tanker. To simulate a refueling scenario, we use ground vehicles to simulate a pseudo tanker and pseudo receiver UAV. Imagery of the receiver is collected by the cameras on the tanker and processed by a …
Exploring Laser Induced Breakdown Spectroscopy (Libs) For Post-Detonation Nuclear Forensics Debris Analysis,
2019
United States Military Academy
Exploring Laser Induced Breakdown Spectroscopy (Libs) For Post-Detonation Nuclear Forensics Debris Analysis, Justin Knoll, Chad Schools, David Fobar
Purdue Workshop on Nonproliferation: Technology and Approaches
In the unlikely but catastrophic event of a nuclear terrorist attack our government leadership will need reliable information to rapidly inform critical decisions. This research explores the use of Laser Induced Breakdown Spectroscopy (LIBS) as a potential analysis tool in the National Technical Nuclear Forensics process. The current state of post detonation nuclear forensics requires ground and air samples be collected and shipped to state-of-the-art laboratories for radiochemical analysis. The samples undergo many measurements and useable data is produced as these measurements are completed. This data flows back into the process to guide additional measurements and inform the process of …
Shaping The Far-Zone Intensity, Degree Of Polarization, Angle Of Polarization, And Ellipticity Angle Using Vector Schell-Model Sources,
2019
Air Force Institute of Technology
Shaping The Far-Zone Intensity, Degree Of Polarization, Angle Of Polarization, And Ellipticity Angle Using Vector Schell-Model Sources, Milo W. Hyde Iv
Faculty Publications
This paper presents a method to control both the shape and polarization of a beam in the far field using a vector Schell-model source. Given a desired far-zone beam shape and polarization, and applying Fourier and statistical optics theory, we derive the requisite second-order moments of said source, discuss what aspects of the far-zone beam can be controlled, and develop a step-by-step procedure for synthesizing the required random vector field instances. We validate this approach with Monte-Carlo wave-optics simulations. The results are found to be in very good agreement with the desired far-zone beam characteristics. The beam-shaping technique developed in …
Fundamental Limits Of Measuring Single-Molecule Rotational Mobility,
2019
Washington University in St Louis
Fundamental Limits Of Measuring Single-Molecule Rotational Mobility, Oumeng Zhang, Matthew D. Lew
Electrical & Systems Engineering Publications and Presentations
Various methods exist for measuring molecular orientation, thereby providing insight into biochemical activities at nanoscale. Since fluorescence intensity and not electric field is detected, these methods are limited to measuring even-order moments of molecular orientation. However, any measurement noise, for example photon shot noise, will result in nonzero measurements of any of these even-order moments, thereby causing rotationally-free molecules to appear to be partially constrained. Here, we build a model to quantify measurement errors in rotational mobility. Our theoretical framework enables scientists to choose the optimal single-molecule orientation measurement technique for any desired measurement accuracy and photon budget.
