Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Nonreciprocity"”.
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Periodic driving and nonreciprocity in cavity optomechanics
Part I of this thesis is concerned with cavity optomechanical systems subject to periodic driving. We develop a Floquet approach to solve time-periodic quantum Langevin equations in the steady state, show that two-time correlation functions of system operators can be expanded in a Fourier series, …
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Nonreciprocal effects and their applications in fiber optic networks
Nonreciprocity is a fundamental property of networks. Unlike electronic networks theory, optical network theory is still a field to be investigated. Lightwave systems, including fiber optic and integrated optic, are becoming more and more complex, new function blocks ( or components) and networking …
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Genetic algorithm gradient ascent (GAGA) optimization of compact symmetry-breaking photonic crystals
… whose structures are optimized to maximize the nonreciprocity of infrared radiation absorptance/emittance in planar and compact designs. Two different mechanisms to enable nonreciprocal infrared absorbers/emitters are simulated and compared – anomalous Hall effect in Weyl semimetals 2 and …
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Elastic wave tailoring at the macro/micro/nano- scales using intentional strongly nonlinear coupling
… acoustic systems—are performed and nonreciprocity is successfully demonstrated, both theoretically and experimentally. This is accomplished using two different schemes: first, a system involving nonlinearity and internal scale hierarchy in mass, and, second, a system consisting of …
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Nonreciprocal and Exotic Radiative Transfer in Type-I Magnetic Weyl Semimetals
… materials—Weyl semimetals—can possess intrinsic nonreciprocity due to the Berry curvature, an internal, pseudo-magnetic field. In this dissertation, we explore thermal radiation from type-I magnetic Weyl semimetals in planar configurations in the far- and near-fields. First, we demonstrate that a …
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Phase-Coherent Drag of Plasmons in a 2D Flowing Fermi Liquid
… surface polarization by the flow results in nonreciprocity: collective modes acquire a ±𝑘 asymmetry in mode dispersion. This thesis explores plasmonic drag in two-dimensional electron fluids with a full account given to the Fermi-liquid interactions. These interactions are essential when the …
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Design and analysis of pattern null reconfigurable antennas
… may suffer from gain compression and exhibit nonreciprocity, setting the stage for additional research to mitigate these effects.
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Dynamic polarizability and collective modes in narrow-band electron systems
… modes. We present a new mechanism for plasmon nonreciprocity the magnitude of which is controllable through the strength of electron-electron interactions, which makes it particularly pronounced in the moiré materials.
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Analysis of Linear and Nonlinear Quasiperiodic Metamaterials with Local Resonators
… This can be used for improved wave guiding, nonreciprocity, and amplitude filtering.
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Wave Engineering in Time Modulated, Nonlinear, and Anisotropic Metamaterials
… for instance realizing nonlinearity-based nonreciprocity, in which the wave itself modulates the medium, overcoming speed limitations. To further increase the efficiency, I will show how nonlinear generation and wave mixing can be obtained in thin 2D periodic structures based on …
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Brillouin scattering induced transparency: Coherent optomechanical interaction leading to slow light and non-reciprocal light transmission
An optical isolator is a device that allows only one-way light transmission. It is an essential optical component used for protection of laser sources found in many applications such as undersea optical communication networks, spectroscopy, fluorescence microscopy, and laser cutting. Today, all …
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Tailoring elastic wave propagation at the macro and microscale via intentional nonlinearity
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2025-05-01
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Acoustic non-reciprocity in passive nonlinear waveguides with configurational asymmetry
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-15 without embargo terms
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Nonreciprocal coupling to microstrip resonators
"Inducing nonreciprocal wave propagation is a fundamental challenge across a wide range of physical systems in electromagnetics, optics, and acoustics. Linear, time-invariant systems are always reciprocal, but reciprocity can be broken through the action of a bias that is asymmetric under …
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Dynamic Metasurfaces for Advanced Applications
<p>To date metamaterials and metasurfaces have been studied for over 20 years. Throughout this time sophisticated understanding of their properties and capabilities has been developed, with many significant and exotic properties such as flat lenses, negative refraction, and perfect absorption. In …
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Nonlinear and Time-Modulated Metamaterials: Applications at Microwave Frequencies
<p>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 …
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Nonlinear wave dynamics of continuum phononic materials with periodic rough contacts
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-03-01 without embargo terms