Electromagnetics and Photonics Commons^™

Evaluation Of The Dynamic Vision Sensor’S Photoreceptor Circuit For Infrared Event-Based Sensing, Zinah M. Alsaad

Electrical and Computer Engineering ETDs

For space surveillance applications, neuromorphic imaging is being studied as it may perform sensing and tracking tasks with less power and downstream datalink demand. The read-out of the event-based camera is made to only be sensitive to changes in the signals it receives from the photodetector, which results in a datastream of events indicating where and when changes in illumination occur. This is in contrast to the conventional framing camera, which produces images by essentially counting the electrons produced by light incident on each pixel’s photodetector. These cameras are commercially available with siliconbased detectors for applications involving visible wavelengths. However, …

Improved Experimental Validation Of An Electromagnetic Subcell Model For Narrow Slots With Depth, Michael Anthony Illescas

Electrical and Computer Engineering ETDs

The coupling of electromagnetic (EM) energy into a system can disrupt operation of essential electronics present within it. Metal enclosures are used to shield these systems from potentially harmful electromagnetic interference (EMI). Seams and gaps in such metal enclosures are minimized but unavoidable for reasons such as maintenance and repair. These seams and gaps create an entry point for EM energy to couple into the system. Entry points are often modeled by EM analysts as narrow slots defined by their length, width, and depth. The depth of these slots can become significant compared to the wavelength, introducing resonances associated with …

Computational Design Of Fiber-Optic Probes For Biosensing, Suwarna Karna

Electrical Engineering Theses

This thesis presents a study on the optical characteristics of hollow-core photonic crystal fibers (HC-PCFs) with a band gap cladding structure and their applications in optical fiber sensing. This 800B HC-PCF exhibited excellent optical properties and has a flexible structure, which makes them suitable for a wide range of industrial applications. Finite element simulations and structural optimization designs were conducted using the surface plasmon resonance (SPR) technique to determine the optimal performance parameters of the 800B HC-PCF. The fiber was further modified using the SPR technique to improve its practical detection capabilities. The performance of the modified fiber was observed …

Implementing Commercial Inverse Design Tools For Compact, Phase-Encoded, Plasmonic Digital Logic Devices, Michael Efseaff, Kyle Wynne, Krishna Narayan, Mark C. Harrison

Engineering Faculty Articles and Research

Numerical simulations have become an essential design tool in the field of photonics, especially for nanophotonics. In particular, 3D finite-difference-time-domain (FDTD) simulations are popular for their powerful design capabilities. Increasingly, researchers are developing or using inverse design tools to improve device footprints and performance. These tools often make use of 3D FDTD simulations and the adjoint optimization method. We implement a commercial inverse design tool with these features for several plasmonic devices that push the boundaries of the tool. We design a logic gate with complex design requirements as well as a y-splitter and waveguide crossing. With minimal code changes, …

Design And Analysis Of High Performance Magnetic Gears For Magnetomechanical Thrusters, Ho Yin Wong

Dissertations and Theses

This dissertation is devoted to investigating the performance potential of coaxial radial flux modulating magnetic gears for use in propulsive thruster applications. The research has focused on studying magnetic gear designs suitable for use in electric aircraft drivetrains and electric boat thrusters. Consequent pole, flux concentration and Halbach rotor magnetic gear typologies have been analyzed and compared with respect to their torque density performance for the first time. It is shown that the Halbach rotor magnetic gear holds the greatest potential with respect to achieving volumetric and mass torque densities parity with an equivalent mechanical gear.

A high volumetric torque …

Characterizing Location-Based Electromagnetic Leakage Of Computing Devices Using Convolutional Neural Networks To Increase The Effectiveness Of Side-Channel Analysis Attacks, Ian C. Heffron

Theses and Dissertations

SCA attacks aim to recover some sort of secret information, often in the form of a cipher key, from a target device. Some of these attacks focus on either power-based leakage, or EM-based leakage. Neural networks have recently gained in popularity as tools in SCA attacks. Near-field EM probes with high-spatial resolution enable attackers to isolate physical locations above a processor. This enables attackers to exploit the spatial dependencies of algorithms running on said processor. These spatial dependencies result in different physical locations above a chip emanating different signal strengths. The strengths of different locations can be mapped using the …

Validation Of Bottom-Up Gnss Radio Occultation Method To Measure D- And E-Region Electron Density, Dylan J. Shaver

Theses and Dissertations

An in-depth validation of a new bottom-up approach using GNSS Radio Occultation (GNSS-RO) data to generate electron density profiles in the D- and E-region ionosphere. This comparison was completed using daytime ionosonde profiles when sporadic-E (E_s) was not present, and corresponding FIRI profiles. The average GNSS-RO profile is a few kilometers higher in altitude than the ionosonde profiles at the minimum frequency, f min. When the ionosonde profiles are shifted so that the altitudes match at f min, they are in good agreement up to the E-region peak altitude, hmE. Below f min, the …

The Electromagnetic Bayonet: Development Of A Scientific Computing Method For Aperture Antenna Optimization, Michael P. Ingold

Theses and Dissertations

The quiet zone of a radar range is the region over which a transmitted EM field approximates a uniform plane wave to within some finite error tolerance. Any target to be measured must physically fit within this quiet zone to prevent excess measurement error. Compact radar ranges offer significant operational advantages for performing RCS measurements but their quiet zone sizes are constrained by space limitations. In this work, a scientific computing approach is used to investigate whether equivalent-current transmitters can be designed that generate larger quiet zones than a conventional version at short range. A time-domain near-field solver, JefimenkoModels, was …

Magnetic Anomaly Mapping For Navigation, Luke T. Bergeron

Theses and Dissertations

Magnetic navigation (MagNav) has the potential to provide a global form of navigation that uses magnetic measurements of the Earth’s anomaly magnetic field and compares those measurements to a magnetic anomaly map in order to determine the user’s position. Widespread use of MagNav will require a database of fully-sampled, low-altitude magnetic anomaly maps. Existing magnetic anomaly map databases usually come from under- or poorly-sampled surveys. In this work, we provide an easy to follow MagNav anomaly map generation framework and set of survey collection metrics/requirements in an effort to help facilitate and standardize the creation of such a database. We …

Evolution Of Coronal Magnetic Field Parameters During X5.4 Solar Flare, Seth H. Garland, Benjamin F. Akers, Vasyl B. Yurchyshyn, Robert D. Loper, Daniel J. Emmons

Faculty Publications

The coronal magnetic field over NOAA Active Region 11,429 during a X5.4 solar flare on 7 March 2012 is modeled using optimization based Non-Linear Force-Free Field extrapolation. Specifically, 3D magnetic fields were modeled for 11 timesteps using the 12-min cadence Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager photospheric vector magnetic field data, spanning a time period of 1 hour before through 1 hour after the start of the flare. Using the modeled coronal magnetic field data, seven different magnetic field parameters were calculated for 3 separate regions: areas with surface |Bz| ≥ 300 G, areas of flare brightening seen …

High-Efficieny Ultrafast Mid-Infrared Source For Strong Field Science, Fangjie Zhou

Electronic Theses and Dissertations, 2020-2023

The potential of high-energy sources within the mid-infrared region (3-8 μm) has garnered significant attention for diverse research and industrial applications. Millijoule pulses extending beyond 3 μm can facilitate the production of x-rays with photon energies in the keV range through high harmonic generation (HHG). These high-energy x-ray pulses enable the characterization of electron dynamics within molecules and condensed matter materials. Additionally, the atmospheric transmission window between 3-5 μm allows lasers within this spectral range to deliver energy efficiently to distant targets via optical filaments without divergence, highlighting promising prospects for defense applications. In contrast to laser amplifiers, which are …

Optical Design Study Of A High-Resolution Spectrograph Utilizing Photonic Lanterns For A Large Fiber Array Telescope, Richard D'Alo

Graduate Thesis and Dissertation 2023-2024

Large area fiber array telescopes are a relatively modern development in the long history of telescope design and effectively create a single large equivalent aperture by combining many smaller unit telescopes at a fraction of the cost. In this study a spectrograph optical design is demonstrated that utilizes photonic lanterns in the input fiber feed for the Large Fiber Array Spectroscopic Telescope (LFAST) design concept, where photonic lanterns provide a simplified approach to the fiber feed originally proposed for LFAST. Conservation of etendue is applied to derive the relationship between slit size and photonic lantern ratio, and classical echelle spectrograph …

Structural Transformations In Photo-Thermo-Refractive Glass For Hologram Recording, Roberto Alejandro Alvarez Aguirre

Electronic Theses and Dissertations, 2020-2023

This dissertation focuses on the structural transformations in photo-thermo-refractive (PTR) glass that enable recording phase holograms for efficient transformation of optical beams and high resolution spectroscopy. PTR glass is a multicomponent silicate matrix doped with Ce, Ag, Sn and Sb. It is a holographic phase medium with the ability of permanent refractive index change after UV exposure and thermal development above 500°C due to the precipitation of a NaF crystalline phase. Electronic processes are studied by analyzing the structure of absorption and luminescence bands of PTR glass matrix and its dopants. We analyze the structural transformations in PTR glass from …

Active Photonic Integrated Devices And Circuits On Thin-Film Lithium Niobate Platform, Ehsan Ordouie

Electronic Theses and Dissertations, 2020-2023

This thesis delves into innovative active photonic integrated devices and circuits on the thin-film lithium niobate (TFLN) platform, focusing on their applications and potential future advancements. We introduce a new family of electrooptic modulators (EOMs), the Four-Phase Electrooptic Modulators (FEOMs), which are fabricated using the TFLN platform. These devices effectively mitigate bandwidth and dynamic-range constraints in optical communication systems by reducing dispersion penalties and common-mode noises. Their functionality is demonstrated in a photonic time-stretch system. A dual-polarization variant further exemplifies the mitigation of both dispersion penalties and common-mode noises in long-haul communication links, marking significant strides towards the practical implementation …

Efficient Design And Implementation Of Miniaturized Microstrip Diplexer Using Dual Open Stub Loaded Resonator For 5g Applications, Islam F. Abu Elkhair, Hamdi A. Elmikati, Mohamed M. Ashour, Amr H. Hussein

Mansoura Engineering Journal

The design and implementation of a compact size diplexer with high isolation, low insertion loss, and small fractional bandwidths is a promising issue in recent wireless communication systems. In this paper, a novel microstrip diplexer has been introduced based on the utilization of the dual open stub loaded resonator technique. The proposed design has a very compact size of with a high operating power efficiency. The diplexer is designed to operate at two resonance frequencies of and with very low insertion losses of and , respectively. Moreover, it provides high isolation values of and for and , respectively. The diplexer …

Validation Of Expanded Trend-To-Trend Cross-Calibration Technique And Its Application To Global Scale, Ramita Shah

Electronic Theses and Dissertations

The expanded Trend-to-Trend (T2T) cross-calibration technique has the potential to calibrate two sensors in much less time and provides trends on daily assessment basis. The trend obtained from the expanded technique aids in evaluating the differences between satellite sensors. Therefore, this technique was validated with several trusted cross-calibration techniques to evaluate its accuracy. Initially, the expanded T2T technique was validated with three independent RadcaTS RRV, DIMITRI-PICS, and APICS models, and results show a 1% average difference with other models over all bands. Further, this technique was validated with other SDSU techniques to calibrate the newly launched satellite Landsat 9 with …

Topological Photonic Metasurfaces For Light Manipulation And Strong Light-Matter Interaction, Svetlana Kiriushechkina

Dissertations and Theses

High-resolution nanopatterning techniques, such as electron beam lithography, extended opportunities for implementation of the various designs of photonic structures which exhibit exciting physical phenomena in the optical domain. A straightforward fabrication of on-slab nanostructures is advantageous for integration with various photonic on-chip devices. Last decade all-dielectric periodic nanostructures (photonic metasurfaces) boost a growth of novel optical technologies, from ultra-sensitive detectors to compact beam structured lasers. Moreover, they represent one of the most promising platforms in which topological phases can be explored and exploited.

Topological photonic structures attract a significant interest owing to their outstanding properties such as a resilience to …

Design And Experimental Observation Of Topological States In Photonic Metasurfaces, Anton Vakulenko

Dissertations and Theses

Topological phases in photonics attract a lot of attention due to their unique properties which allow controlling optical coupling and electromagnetic field distributions in nanostructures. Diverse phenomena supported by photonic topological structures include robust scatter-free waveguiding, an extreme confinement of light, lasing and strong coupling with novel low- dimensional materials. A very convenient integration with on-chip optical devices and also with quantum dots or monolayers of van der Waals materials promise even brighter future for photonic topological insulators as a useful platform for innovative photonic and compact quantum devices.

In the course of my dissertation work, I investigated topological structures …

Nonlinear And Time-Modulated Metamaterials: Applications At Microwave Frequencies, Hady Mohammed Saied Sayed Moussa

Dissertations and Theses

Metamaterials (the Greek prefix meta, means beyond) are artificially structured materials that interact with the incoming waves in extraordinary ways, beyond the properties of natural materials, yielding unusual and exotic electromagnetics phenomena. By careful engineering of the material properties, invoking nonlinear elements and/or time-modulating some of the material parameters, linearity and/or time-invariance can be broken in metamaterials, enabling extraordinary wave phenomena that open opportunities for the microwave engineering community, including the creation of nonreciprocal devices, frequency conversion, and more. In this dissertation, we explore, investigate, design, and fabricate metamaterials that open new applications for nonlinearity-based and time-varying devices, particularly in …

A High-Precision Electron Emission Model: Computational Methods For Nanoscale Structures, Alister J. Tencate

Graduate Research Theses & Dissertations

The high-intensity, high-brightness and precision frontiers for charged particle beams are an increasingly important focus for study. Electron microscopy has demonstrated high quality beams from a single nanotip emitter, and cathodes of structured nanoscale arrays show promise as ultracold electron sources. Optimization of the cathode design for precision applications necessitates a detailed treatment of the interplay between the structure geometry, quantum mechanical emission mechanism, and electromagnetic interactions between the emitted electrons and the boundary interface. This dissertation details the numerical tools developed to simulate these processes efficiently with enough fidelity to be accurate even in the ultracold regime.

Conventional simulation …