Electromagnetics and Photonics Commons^™

Wideband And Flat-Gain Optical Amplifier With Hafnia-Bismuth Erbium Co-Doped Fiber, Abduljabbar Al-Azzawi Alabbas Ahmed

Student Works (2020-2029)

A compact optical amplifier with a flat-gain characteristic is demonstrated using hafnia bismuth-erbium co-doped fiber (HB-EDF) as the gain medium. The HB-EDF was recently fabricated using a modified chemical vapor deposition (MCVD) process in conjunction with solution doping (SD) technique. The fiber has an Erbium ions concentration of 12500 wt. ppm, which was realized due to the co-doping with Hafnium and Aluminum ions. Firstly, the proposed amplifier was investigated for both single and double-pass configurations. It is found that the 0.5m long HB-EDF is the optimum length for the C-band region. For double-pass HB-EDFA, at input signal power of -10 …

Advancing Compact Pulsed Power, Jon C. Pouncey

Electrical and Computer Engineering ETDs

The first two decades of the 21^st century have seen significant interest in expanding the application of pulsed power technology beyond its traditional use in physics and nuclear weapons research. Applications in the field of national defense, which present unique constraints on system size, have provided impetus to increase the exploration of compact pulsed power solutions. Innovations related to energy density, insulation, switching, and power conversion systems have been realized, bringing deployable compact pulsed power systems closer to realization than ever before. However, recent systems integration efforts have shown that work still remains to develop needed tools and technologies …

Ensemble Malware Classification System Using Deep Neural Networks, Barath Narayanan Narayanan, Venkata Salini Priyamvada Davuluru

Electrical and Computer Engineering Faculty Publications

With the advancement of technology, there is a growing need of classifying malware programs that could potentially harm any computer system and/or smaller devices. In this research, an ensemble classification system comprising convolutional and recurrent neural networks is proposed to distinguish malware programs. Microsoft's Malware Classification Challenge (BIG 2015) dataset with nine distinct classes is utilized for this study. This dataset contains an assembly file and a compiled file for each malware program. Compiled files are visualized as images and are classified using Convolutional Neural Networks (CNNs). Assembly files consist of machine language opcodes that are distinguished among classes using …

Resonant Metagratings For Spectral And Angular Control Of Light For Colored Rooftop Photovoltaics, Floris Uleman, Andrea Cordaro, Andrea Alù, Albert Polman

Advanced Science Research Center

We designed semitransparent metagrating supercells that enable control over the spectrum and directivity of incident light for applications in photovoltaics with tailored angular appearance. The building block of the supercells is a 100–120 nm wide and 175 nm tall silicon nanowire that shows a strong Mie resonance around λ = 650 nm. By arranging the resonant Mie scatterers into metagratings of increasing pitch (675–1300 nm), we created a Lambertian-like scattering distribution over an angular range of choice. The millimeter-sized metasurfaces were fabricated using electron beam lithography and reactive ion etching. The fabricated metasurface nearly fully suppresses specular reflection on resonance …

Evaluating The Effects Of Electric And Magnetic Loading On The Performance Of Single And Double Rotor Axial Flux Pm Machines, Narges Taran, Greg Heins, Vandana Rallabandi, Dean Patterson, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Axial flux PM (AFPM) machines are used particularly in applications requiring a compact structure. Their disc shape topology and axial air-gap have led to a variety of configurations including two popular ones: the yokeless and segmented armature (YASA), and the single-stator single rotor or single sided machine. In this study, a comprehensive comparative analysis of these configurations is conducted at different magnetic and electric loadings. It is found that at lower loadings, typically employed for air-cooled machines, the torque/ampere characteristics of the YASA machine are almost identical to those of a single sided machine constructed with half the magnet volume. …

Single-Pulse, Kerr-Effect Mueller Matrix Lidar Polarimeter, Keyser, Christian K., Richard K. Martin, Helena Lopez-Aviles, Khanh Nguyen, Arielle M. Adams, Demetrios Christodoulides

Faculty Publications

We present a novel light detection and ranging (LiDAR) polarimeter that enables measurement of 12 of 16 sample Mueller matrix elements in a single, 10 ns pulse. The new polarization state generator (PSG) leverages Kerr phase modulation in a birefringent optical fiber, creating a probe pulse characterized by temporally varying polarization. Theoretical expressions for the Polarization State Generator (PSG) Stokes vector are derived for birefringent walk-off and no walk-off and incorporated into a time-dependent polarimeter signal model employing multiple polarization state analyzers (PSA). Polarimeter modeling compares the Kerr effect and electro-optic phase modulator–based PSG using a single Polarization State Analyzer …

Development Of A Monolithic Implantable Neural Interface From Cubic Silicon Carbide And Evaluation Of Its Mri Compatibility, Mohammad Beygi

USF Tampa Graduate Theses and Dissertations

One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from device material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. In the first section of this dissertation, the fabrication and initial electrochemical characterization of a monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe is reported. …

Focused Beam System Biaxial Material Characterization, Nicholas A. O'Gorman

Theses and Dissertations

Electromagnetic material characterization is the process of determining the constitutive parameters (complex permittivity and permeability) of given a sample. Due to the large number of unknowns involved, multiple unique measurements are required for material property extraction. Many measurement methods, such as waveguides and striplines, possess a rigid internal structure that the sample being measured must adhere to. This rigidity limits these methods to samples that fit within the device and inhibits oblique sample orientations, limiting the number of independent measurements that can be obtained. A focus beam system, due to being an open system with greater freedom in sample size …

Characterization And Sensitivity Analysis Of 6 Meter Cassegrain Antenna, James L. Harris

Theses and Dissertations

This paper will characterize a 6 meter in diameter cassegrain antenna. The cassegrain antenna is a special form of a dual reflector antenna which uses a main reflector following a parabolic curve and a sub reflector which follows a hyperbolic curve. Cassegrain style antennas have multiple parameters which can be tuned to achieve specific design goals. Performing a sensitivity analysis will establish relationships between design parameters, directivity, side lobe levels, and effects of strut geometry. The initial design parameters will be assumed based on typical values. Results from the sensitivity analysis will be used to provide a performance band for …

Dynamic Micromechanical Fabry-Perot Cavity Sensors Fabricated By Multiphoton Absorption Onto Optical Fiber Tips, Jeremiah C. Williams

Theses and Dissertations

This research leveraged two-photon polymerization microfabrication to integrate dynamic mechanical components with Fabry-Perot resonators onto the ends of low-loss optical fibers to prototype 3 micro-optic devices. The first device featured a multi-positional mirror that enabled thin-film deposition onto cavities of any length with mirrors of significant curvature, for refractive index sensing. The second device combined an FP cavity with a spring body featuring easily scalable stiffness for pressure sensing. The third device presented a high-speed rotating micro-anemometer for measuring a wide range of gas flows. All devices represent a significant reduction in size and weight over commercially available devices.

Structural And Electronic Properties Of The Pure And Stable Elemental 3d Topological Dirac Semimetal Α-Sn, Maya N. Nair, Ivan Madarevic, Umamahesh Thupakula, Gertjan Lippertz, Niels Claessens, Pin-Cheng Lin, Harsh Bana, Sara Gonzalez, Giovanni Di Santo, Luca Petaccia, Lino M.C. Pereira, Chris Van Haesendonck, Margriet J. Van Bael

Advanced Science Research Center

In-plane compressively strained α-Sn films have been theoretically predicted and experimentally proven to possess non-trivial electronic states of a 3D topological Dirac semimetal. The robustness of these states typically strongly depends on purity, homogeneity, and stability of the grown material itself. By developing a reliable fabrication process, we were able to grow pure strained α-Sn films on InSb(100), without heating the substrate during growth nor using any dopants. The α-Sn films were grown by molecular beam epitaxy, followed by experimental verification of the achieved chemical purity and structural properties of the film’s surface. Local insight into the surface morphology was …

Syllabus Ee330 Electromagnetics, Nicholas Madamopoulos

Open Educational Resources

Concepts covered in the undergraduate electrical engineering class of electromagnetics

Magslam: Aerial Simultaneous Localization And Mapping Using Earth's Magnetic Anomaly Field, Taylor N. Lee, Aaron J. Canciani

Faculty Publications

Instances of spoofing and jamming of global navigation satellite systems (GNSSs) have emphasized the need for alternative navigation methods. Aerial navigation by magnetic map matching has been demonstrated as a viable GNSS‐alternative navigation technique. Flight test demonstrations have achieved accuracies of tens of meters over hour‐long flights, but these flights required accurate magnetic maps which are not always available. Magnetic map availability and resolution vary widely around the globe. Removing the dependency on prior survey maps extends the benefits of aerial magnetic navigation methods to small unmanned aerial systems (sUAS) at lower altitudes where magnetic maps are especially undersampled or …

Improving Aeromagnetic Calibration Using Artificial Neural Networks, Mitchell C. Hezel

Theses and Dissertations

The Global Positioning System (GPS) has proven itself to be the single most accurate positioning system available, and no navigation suite is found without a GPS receiver. Even basic GPS receivers found in most smartphones can easily provide high quality positioning information at any time. Even with its superb performance, GPS is prone to jamming and spoofing, and many platforms requiring accurate positioning information are in dire need of other navigation solutions to compensate in the event of an outage, be the cause hostile or natural. Indeed, there has been a large push to achieve an alternative navigation capability which …

Measurement Of The 160Gd(P,N)160Tb Excitation Function From 4 18 Mev, Using A Stacked Foil Technique, Ryan K. Chapman

Theses and Dissertations

A stack of thin Gd, Ti, and Cu foils were irradiated with an 18 MeV proton beam at Lawrence-Berkeley National Laboratory's 88-Inch Cyclotron to investigate the ¹⁶⁰Gd(p,n)¹⁶⁰Tb nuclear reaction for nuclear forensics applications. This experiment will improve knowledge of ¹⁶⁰Tb production rates, allowing ¹⁶⁰Tb to be efficiently created in a foil stack consisting of other proton induced isotopes for forensics applications. A set of 15 measured cross sections between 4-18 MeV for ¹⁶⁰Gd(p,n)¹⁶⁰Tb were obtained using a stacked foil technique. The foil stack consisted of one stainless steel, one iron, fifteen gadolinium, …

Detection Of Reconnection Signatures In Solar Flares, Taylor R. Whitney

Theses and Dissertations

Solar flare forecasting is limited by the current understanding of mechanisms that govern magnetic reconnection, the main physical phenomenon associated with these events. As a result, forecasting relies mainly on climatological correlations to historical events rather than the underlying physics principles. Solar physics models place the neutral point of the reconnection event in the solar corona. Correspondingly, studies of photospheric magnetic fields indicate changes during solar flares -- particularly in relation to the field helicity -- on the solar surface as a result of the associated magnetic reconnection. This study utilizes data from the Solar Dynamics Observatory (SDO) Helioseismic and …

Neutron Displacement Damage In Germanium Tin Photodiodes, Nathan J. Gale

Theses and Dissertations

GeSn is a promising material for photodiodes in the near-to-mid infrared (IR) spectrum because of new growth methods that enable integration with complementary metal oxide semiconductor (CMOS) technology. While natural germanium has a threshold wavelength of 1800 nm, 6.9 Sn content extends the threshold wavelength to 2700 nm based on a Sn content dependent bandgap. Also, unlike other semiconductors that require liquid nitrogen cooling to act as an IR sensor, GeSn can be operated at room temperature, enabling a wide variety of applications. In this study, photodiodes ranging from 0 to 6.9 tin content were subjected to 1 MeV (Si) …

Synthesizing General Electromagnetic Partially Coherent Sources From Random, Correlated Complex Screens, Milo W. Hyde Iv

Faculty Publications

We present a method to generate any genuine electromagnetic partially coherent source (PCS) from correlated, stochastic complex screens. The method described here can be directly implemented on existing spatial-light-modulator-based vector beam generators and can be used in any application which utilizes electromagnetic PCSs. Our method is based on the genuine cross-spectral density matrix criterion. Applying that criterion, we show that stochastic vector field realizations (corresponding to a desired electromagnetic PCS) can be generated by passing correlated Gaussian random numbers through “filters” with space-variant transfer functions. We include step-by-step instructions on how to generate the electromagnetic PCS field realizations. As an …

Wireless Underground Communications In Sewer And Stormwater Overflow Monitoring: Radio Waves Through Soil And Asphalt Medium, Usman Raza, Abdul Salam

Computer Information Technology Faculty Publications

Storm drains and sanitary sewers are prone to backups and overflows due to extra amount wastewater entering the pipes. To prevent that, it is imperative to efficiently monitor the urban underground infrastructure. The combination of sensors system and wireless underground communication system can be used to realize urban underground IoT applications, e.g., storm water and wastewater overflow monitoring systems. The aim of this article is to establish a feasibility of the use of wireless underground communications techniques, and wave propagation through the subsurface soil and asphalt layers, in an underground pavement system for storm water and sewer overflow monitoring application. …

Inhibiting Surface Flashover In Vacuum With High Gradient Insulators, Cameron Harjes

Electrical and Computer Engineering ETDs

In high voltage systems, insulators may be used to separate conductors and these insulators are typically the limiting factor in the system’s operating voltage. When the voltage between two conductors is too large, the insulators can fail due to surface flashover. As systems become more compact, the threat of failure by insulator flashover increases, making the optimization of insulators a critical task for reliability.

Insulators at a vacuum interface are especially vulnerable to surface flashover. Insulators have been shown to holdoff more voltage in vacuum after being baked to remove imbedded surface gases. Ceramic materials are particularly attractive because, unlike …