Electromagnetics and Photonics Commons^™

Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger

Electronic Theses and Dissertations

Absorption plays a critical role in a variety of optical applications – sometimes it is desirable to minimize it as in optical fibers and waveguides, or to enhance it as in solar cells and photodetectors. We describe here a new optical scheme that controllably produces high optical absorption over a broad wavelength range (hundreds of nm) in systems that have low intrinsic absorption over the same range. This effect, 'coherent perfect absorption' or CPA, arises from a subtle interplay between interference and absorption of two beams incident on a weakly absorbing medium. In the first part of this study, we …

Boost Battery, Samuel Rauch, Alvin Ng, Lacy Sigman

Electrical Engineering

In modern times, the problem of a depleted battery confronts us too often. Whether it appears with a smartphone or with any other electronic device, the situation frustrates all consumers. This project designs and constructs a compact portable battery charger that charges through kinetic energy. Thus, one can perform everyday activities, such as walking or running, and charge up a backup battery with no extra effort or time. Additionally, an attachable band harvests thermal energy to maximize the amount of clean power generated. Energy harvesting from kinetic motion and thermal differences provide users with power when no actual power suppliers …

Short Wave Infrared Imaging System For Night And Day Long Range Facial Recognition And Surveillance, Robert B. Martin

Graduate Theses, Dissertations, and Problem Reports (ETD)

The capability to detect, observe, and positively identify people at a distance is important to numerous security and defense applications. Traditional solutions for human detection and observation include long-range visible imagers for daytime and thermal infrared imagers for night-time use. Positive identification, through computer face recognition, requires facial imagery that can be repeatably matched to a database of visible spectrum facial mug shots. Nighttime identification at large distances is not possible with visible imagers due to lack of light, or with thermal infrared imagers due to poor correlation with visible facial imagery. An active-SWIR imaging system was developed that is …

High Efficiency And Wide Color Gamut Liquid Crystal Displays, Zhenyue Luo

Electronic Theses and Dissertations

Liquid crystal display (LCD) has become ubiquitous and indispensable in our daily life. Recently, it faces strong competition from organic light emitting diode (OLED). In order to maintain a strong leader position, LCD camp has an urgent need to enrich the color performance and reduce the power consumption. This dissertation focuses on solving these two emerging and important challenges. In the first part of the dissertation we investigate the quantum dot (QD) technology to improve the both the color gamut and the light efficiency of LCD. QD emits saturated color and grants LCD the capability to reproduce color vivid images. …

Entanglement And Coherence In Classical And Quantum Optics, Kumel Kagalwala

Electronic Theses and Dissertations

We explore the concepts of coherence and entanglement as they apply to both the classical and quantum natures of light. In the classical domain, we take inspiration from the tools and concepts developed in foundational quantum mechanics and quantum information science to gain a better understanding of classical coherence theory of light with multiple degrees of freedom (DoFs). First, we use polarization and spatial parity DoFs to demonstrate the notion of classical entanglement, and show that Bell's measure can serve as a useful tool in distinguishing between classical optical coherence theory. Second, we establish a methodical yet versatile approach called …

Atmospheric Pressure Chemical Vapor Deposition Of Functional Oxide Materials For Crystalline Silicon Solar Cells, Kristopher Davis

Electronic Theses and Dissertations

Functional oxides are versatile materials that can simultaneously enable efficiency gains and cost reductions in crystalline silicon (c-Si) solar cells. In this work, the deposition of functional oxide materials using atmospheric pressure chemical vapor deposition (APCVD) and the integration of these materials into c-Si solar cells are explored. Specifically, thin oxide films and multi-layer film stacks are utilized for the following purposes: (1) to minimize front surface reflectance without increasing parasitic absorption within the anti-reflection coating(s); (2) to maximize internal back reflectance of rear passivated cells, thereby increasing optical absorption of weakly absorbed long wavelength photons (? > 900 nm); (3) …

White Light Continuum For Broadband Nonlinear Spectroscopy, Trenton Ensley

Electronic Theses and Dissertations

Supercontinuum (SC) generation, oftentimes referred to as white-light continuum (WLC), has been a subject of interest for more than 40 years. From the first observation of WLC in condensed media in the early 1970s to the first observation of WLC in gases in the mid-1980s, much work has been devoted to developing a framework for understanding the complex nature of this phenomenon as well as discovering its utility in various applications. The main effort of this dissertation is to develop a WLC for the purpose of broadband nonlinear spectroscopy and use it in spectroscopic measurements. The ability to generate a …

Two-Photon Absorption In Bulk Semiconductors And Quantum Well Structures And Its Applications, Himansu Pattanaik

Electronic Theses and Dissertations

The purpose of this dissertation is to provide a study and possible applications of two-photon absorption (2PA), in direct-gap semiconductors and quantum-well (QW) semiconductor structures. One application uses extremely nondegenerate (END) 2PA, for mid-infrared (mid-IR) detection in uncooled semiconductors. The use of END, where the two photons have very different energies gives strong enhancement comapared to degenerate 2PA. This END-2PA enhanced detection is also applied to mid-IR imaging and light detection and ranging (LIDAR) in uncooled direct-gap photodiodes. A theoretical study of degenerate 2PA (D-2PA) in quantum wells, QWs, is presented, along with a new theory of ND 2PA in …

Conservation Laws And Electromagnetic Interactions, Veerachart Kajorndejnukul

Electronic Theses and Dissertations

Aside from energy, light carries linear and angular momenta that can be transferred to matter. The interaction between light and matter is governed by conservation laws that can manifest themselves as mechanical effects acting on both matter and light waves. This interaction permits remote, precise, and noninvasive manipulation and sensing at microscopic levels. In this dissertation, we demonstrated for the first time a complete set of opto-mechanical effects that are based on nonconservative forces and act at the interface between dielectric media. Without structuring the light field, forward action is provided by the conventional radiation pressure while a backward movement …

Photon Statistics In Disordered Lattices, Hasan Kondakci

Electronic Theses and Dissertations

Propagation of coherent waves through disordered media, whether optical, acoustic, or radio waves, results in a spatially redistributed random intensity pattern known as speckle -- a statistical phenomenon. The subject of this dissertation is the statistics of monochromatic coherent light traversing disordered photonic lattices and its dependence on the disorder class, the level of disorder and the excitation configuration at the input. Throughout the dissertation, two disorder classes are considered, namely, diagonal and off-diagonal disorders. The latter exhibits disorder-immune chiral symmetry -- the appearance of the eigenmodes in skew-symmetric pairs and the corresponding eigenvalues in opposite signs. When a disordered …

Electromagnetic Compatibility In Power Inverter Design, Natalia Bondarenko

Doctoral Dissertations

"Power inverter systems generate significant electromagnetic emissions. Methods were studied to model these systems and to reduce their emissions. Three topics are presented in this dissertation.

Methods were developed to obtain simple SPICE models for complex systems which relate circuit components to physical geometry within the system. These models were derived using measurements or using partial element equivalent circuit (PEEC) and model size reduction techniques developed in this dissertation. Methods were proposed for developing a measurement-based model and were applied to a real power inverter/motor system. The model was used to identify system geometries responsible for critical resonances and to …

Pulsed Inductive Plasma Studies By Spectroscopy And Internal Probe Methods, Warner C. Meeks

Doctoral Dissertations

The broad effort of the Missouri Plasmoid Experiment is to elucidate the energy conversion processes in a pulsed inductive discharge due to the presence of plasma. The test article is a 440 to 490 kHz theta-pinch (or solenoidal) geometry coil with a stored energy of around 80 joules. In this work experimental hydrogen, helium, argon and xenon data at back-fill pressures of 10 to 100 mTorr (1.3 to 133.3 Pa) are obtained and interpreted. Spectral and internal probe studies were performed on MPX Mk.I and Mk.II devices, respectively. IR spectra were acquired in the Mk.I device for argon and xenon. …

Near-Field Scanning Study For Radio Frequency Interference Estimation, Jingnan Pan

Doctoral Dissertations

"This dissertation discusses the novel techniques using near-fields scanning to do radio frequency interference (RFI) estimation. As the electronic products are becoming more and more complicated, the radio frequency (RF) receiver in the system is very likely interfered by multiple noise sources simultaneously. A method is proposed to identify the interference from different noise sources separately, even when they are radiating at the same time. This method is very helpful for engineers to identify the contribution of the coupling from different sources and further solve the electromagnetic interference issues efficiently. On the other hand, the equivalent dipole-moment models and a …

Comparison Of Lock-In And Pulse-Phase Thermography For Defect Characterization In Frp Composites Applied To Concrete, Jeff Brown, Sai Harsha Chittineni

Publications

Thermal imaging is a well-established technique for the non-destructive evaluation of FRP composites applied to reinforced concrete. Defect characterization using IR thermography, however, remains a topic of on-going research, and there are currently no universally accepted standards for data collection or interpretation. This research involved large scale thermography inspection of two FRP strengthened bridge girders that were removed from service after approximately 10 years of service in a potentially corrosive marine environment. Trial inspections were performed on test areas where defects could be identified using sounding methods. Two procedures showed the most promise for identifying and characterizing defects: sinusoidal (lock-in …

Properties Of Exchange Coupled All-Garnet Magneto-Optic Thin Film Multilayer Structures, Mohammed Nur-E-Alam, Mikhail Vasilev, Viacheslav A. Kotov, Dmitry Balabanov, Ilya Akimov, Kamal Alameh

Research outputs 2014 to 2021

The effects of exchange coupling on magnetic switching properties of all-garnet multilayer thin film structures are investigated. All-garnet structures are fabricated by sandwiching a magneto-soft material of composition type Bi_1.8Lu_1.2Fe_3.6Al_1.4O₁₂ or Bi₃Fe₅O₁₂:Dy₂O₃ in between two magneto-hard garnet material layers of composition type Bi₂Dy₁Fe₄Ga₁O₁₂ or Bi₂Dy₁Fe₄Ga₁O₁₂:Bi₁₂O₃. The fabricated RF magnetron sputtered exchange-coupled all-garnet multilayers demonstrate a very attractive combination of …

Tunable Optical Nanocavity Of Iron-Garnet With A Buried Metal Layer, Alexey N. Kuz'michev, Lars E. Kreilkamp, Mohammed Nur-E-Alam, Evgeni Bezus, Mikhail Vasilev, Iliya A. Akimov, Kamal Alameh, Manfred Bayer, Vladimir I. Belotelov

Research outputs 2014 to 2021

We report on the fabrication and characterization of a novel magnetophotonic structure designed as iron garnet based magneto-optical nanoresonator cavity constrained by two noble metal mirrors. Since the iron garnet layer requires annealing at high temperatures, the fabrication process can be rather challenging. Special approaches for the protection of metal layers against oxidation and morphological changes along with a special plasma-assisted polishing of the iron garnet layer surface were used to achieve a 10-fold enhancement of the Faraday rotation angle (up to 10.8°=μm) within a special resonance peak of 12 nm (FWHM) linewidth at a wavelength of 772 nm, in …