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Electromagnetics and Photonics Commons™

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2024

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Articles 91 - 97 of 97

Full-Text Articles in Electromagnetics and Photonics

Hybrid Design Approaches For Reconfigurable Em Structures, Jonathan D. Lundquist Jan 2024

Hybrid Design Approaches For Reconfigurable Em Structures, Jonathan D. Lundquist

Theses and Dissertations

The modern world is replete with reasons for employing reconfigurable electromagnetic (EM) structures, but some of the most pressing needs require advancements in power consumption, speed, and footprint [1]. Next generation air defense (NGAD) fighters could benefit from new electronic warfare (EW) countermeasures [2], as well as adaptive stealth technology [3], while doctors could benefit from reconfigurable microwave ablation antennas that can modify radiation pattern and input impedance to match changes in tissue during ablation and account for variations in tumor shapes [4]. The future of antennas, filters, and lenses is reconfigurable as real-world matters of life and death may …


Machine Learning Assisted Optimization For Calculation And Automated Tuning Of Antennas, Lauren Linkous Jan 2024

Machine Learning Assisted Optimization For Calculation And Automated Tuning Of Antennas, Lauren Linkous

Theses and Dissertations

The Antenna Calculation and Autotuning Tool (AntennaCAT) software suite represents a significant advancement in the field of antenna design by automating the entire design, CAD, simulation, and optimization process compatible with several EM simulation software suites. It is the first comprehensive implementation of machine learning in this context. In particular, this work includes the capability to create and export structured datasets from the aforementioned EM software for iterative improvement and includes an expandable selection of optimizers.


Bridging The Gap In Epsilon-Near-Zero Nonlinear Materials, Adam R. Ball Jan 2024

Bridging The Gap In Epsilon-Near-Zero Nonlinear Materials, Adam R. Ball

Theses and Dissertations

Studying how light and matter interact has been of interest to humans for thousands of years. From the invention of the first mirror, burning ants with a magnifying glass, to optical fiber communication, light has been central to mankind. Researchers have sought to take this to the extreme with nonlinear optics where intense laser light interacts with materials. The study of this thesis is to understand a new generation of materials that has come to light. Epsilon-near-zero (ENZ) materials have shown promise for ultrafast light manipulation in tandem with modern day CMOS compatible electronics. Here, I seek to bridge the …


Magnetotransport Properties Of Dirac Semimetal Taco2te2 And Ferromagnetic Weyl Semimetal Co3sn2s2, Samuel Pate Jan 2024

Magnetotransport Properties Of Dirac Semimetal Taco2te2 And Ferromagnetic Weyl Semimetal Co3sn2s2, Samuel Pate

Graduate Research Theses & Dissertations

This dissertation investigates the magnetotransport properties of topological semimetals, specifically focusing on the Dirac semimetal TaCo2Te2 and the Weyl semimetal Co3Sn2S2. In TaCo2Te2, I observed extremely large magnetoresistance that violates Kohler’s rule. Extended Kohler’s rule can be applied with a calculation of Hall factor at low temperatures. I also explored the applicability of the two-band and four-band models of carrier analysis and correlate the region where Kohler’s rule is obeyed to the four-band model. In Co3Sn2S2, I explored the angle-dependent anomalous Hall effect (AHE) near the Kagome plane, revealing a tunable AHE under applied fields and an abrupt disappearance of …


Design And Fabrication Of Quantum Cascade Laser Tree Arrays, Luke Milbocker Jan 2024

Design And Fabrication Of Quantum Cascade Laser Tree Arrays, Luke Milbocker

Graduate Thesis and Dissertation 2023-2024

Quantum cascade lasers (QCLs) are semiconductor lasers that can be designed to emit over a very broad wavelength range from the mid-wave infrared (MWIR) to terahertz frequencies. Their compact size and ability to output several watts of MWIR or long-wave infrared (LWIR) radiation makes them ideal sources for directional infrared counter measures (DIRCM). This application is fueling demand for ever more powerful QCLs, but power gains from single QCLs have largely stagnated in recent years. Novel waveguide geometries such as tree-arrays seek to increase output power delivered in a single high-quality beam. InGaAs/AlInAs tree array QCLs based on ridge waveguides …


Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi Jan 2024

Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi

Chemistry & Biochemistry Faculty Publications

We investigate switching of photoluminescence (PL) from PbS quantum dots (QDs) crosslinked with two different types of photochromic diarylethene molecules, 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (1H) and 4,4'-(1-perfluorocyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (2F). Our results show that the QDs crosslinked with the hydrogenated molecule (1H) exhibit a greater amount of switching in photoluminescence intensity compared to QDs crosslinked with the fluorinated molecule (2F). With a combination of differential pulse voltammetry and density functional theory, we attribute the different amount of PL switching to the different energy levels between 1H and 2F molecules which result in different potential barrier …


Tailored Micromagnet Sorting Gate For Simultaneous Multiple Cell Screening In Portable Magnetophoretic Cell-On-Chip Platforms, Jonghwan Yoon, Yumin Kang, Hyeonseol Kim, Abbas Ali, Keonmok Kim, Sri Ramulu Torati, Mi-Young Im, Changyeop Jeon, Byeonghwa Lim, Cheolgi Kim Jan 2024

Tailored Micromagnet Sorting Gate For Simultaneous Multiple Cell Screening In Portable Magnetophoretic Cell-On-Chip Platforms, Jonghwan Yoon, Yumin Kang, Hyeonseol Kim, Abbas Ali, Keonmok Kim, Sri Ramulu Torati, Mi-Young Im, Changyeop Jeon, Byeonghwa Lim, Cheolgi Kim

Center for Bioelectronics Publications

Conventional magnetophoresis techniques for manipulating biocarriers and cells predominantly rely on large-scale electromagnetic systems, which is a major obstacle to the development of portable and miniaturized cell-on-chip platforms. Herein, a novel magnetic engineering approach by tailoring a nanoscale notch on a disk micromagnet using two-step optical and thermal lithography is developed. Versatile manipulations are demonstrated, such as separation and trapping, of carriers and cells by mediating changes in the magnetic domain structure and discontinuous movement of magnetic energy wells around the circumferential edge of the micromagnet caused by a locally fabricated nano-notch in a low magnetic field system. The motion …