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 20 of 36 for “"Terahertz Spectroscopy"”.
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Ultrafast Broadband Terahertz Spectroscopy
This dissertation centers on broadband terahertz spectroscopy and is arranged in four main sections. In the first section, we describe terahertz generation from a two-color laser air breakdown plasma. This is modeled with a plasma current that includes plasma density and dispersion in propagation. …
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Terahertz spectroscopy of quantum spin liquids
… ZnCu₃(OH)₆Cl₂, are studied by means of Terahertz Time-Domain Spectroscopy. Herbertsmithite is proposed to exhibit Quantum Spin Liquid behavior, in which electron spins have strong antiferromagnetic interactions, but quantum fluctuations inhibit magnetic order even at 0 K, instead giving …
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Developments and advances in nonlinear terahertz spectroscopy
Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present several advances in nonlinear THz spectroscopy that expand the range of …
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A Study of miniature methods of terahertz spectroscopy
Compared to the history of science, spectroscopy at terahertz frequencies is a relatively recent development. Terahertz instruments were initially large and inefficient due to the characteristics of available technology. With progress in materials science and miniature circuit manufacturing …
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The use of terahertz spectroscopy for biomolecular analysis
Terahertz radiation occupies part of the electromagnetic spectrum between the mid-infraredand microwave bands (approximately 0.1 - 20 THz). Within this range, spectroscopic analysis of biological molecules can detect low-frequency vibrational modes that arise from intermolecular as well as …
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Ultrafast Terahertz Spectroscopy of Collective Excitations in Correlated Materials
… excitations in solids is through ultrafast spectroscopy. In this technique, an intense, ultrashort “pump” laser pulse drives the material out of equilibrium, and a subsequent weaker “probe” pulse detects the altered state of the system. By tailoring the parameters of the pump pulse, one can …
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Ultrafast terahertz spectroscopy and control of collective modes in semiconductors
… dissertation we applied methods of ultrafast terahertz (THz) spectroscopy to study several aspects of semiconductor physics and in particular of collective mode excitations in semiconductors. We detect and analyze THz radiation emitted by these collective modes to reveal the underlying physics …
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Contact-free Electrical Characterisation of Novel Materials Using Terahertz Spectroscopy
Terahertz spectroscopy is a powerful, contact-free and non-ionizing technique that allows the accurate measurement of the optoelectronic properties of semiconductor nanomaterials. The detrimental non-radiative pathways, either via surface states or oxidation or defects, that significantly degrades …
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Beyond linear responses: exploring magnetic materials through nonlinear terahertz spectroscopy
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01
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Terahertz Spectroscopy of Topological Insulators and other 2-Dimensional Materials
… the optical behavior of Dirac materials using terahertz time domain spectroscopy (THz-TDS) contact-free optical technique, used to probe the low-energy excitations in strongly correlated electron gases. Chapter 1 provides a broad introduction to the field of topological insulators and graphene …
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Photoinduced Dynamics Studied using Single-Shot Optical and Terahertz Spectroscopy
… echelon-based ultrafast single-shot optical and terahertz (THz) spectroscopy to study irreversible photoinduced dynamics and materials far from equilibrium. First, we motivate the understanding of photoinduced material responses as initiated by, and probed with, ultrafast laser pulses, including …
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Evaluation of Non-Covalent Interaction Models in Molecular Crystals Using Terahertz Spectroscopy
… of solid-state crystalline materials. Since THz spectroscopy is sensitive to both the intermolecular and intramolecular forces that govern the formation of crystalline materials, it is an ideal tool to investigate the accuracy of calculated DFT crystal structures and their vibrational spectra. …
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Investigating the Variations in Molecular Mobility within Amorphous Formulations using Terahertz Spectroscopy
… to recrystallisation over time. In this thesis, terahertz time-domain spectroscopy (THz-TDS) was used to probe variations in molecular mobility within different amorphous systems, with the aim of predicting physical stability based on these changes. The investigation began with a basic …
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Dynamics of lattice vibrations, molecular rotations and spins studied by terahertz spectroscopy
… using organic nonlinear optical crystals and spectroscopy experiments utilizing THz pulses to study the linear and nonlinear responses of molecular dipole, spin, and lattice degrees of freedom in molecular and condensed-matter systems. We have developed several THz spectroscopy methods …
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Ultrafast Terahertz Spectroscopy for the Manipulation and Elucidation of Correlated Quantum Materials
… on top of one another. A variety of Optical-Pump Terahertz-Probe spectroscopic methods are used to drive a system out of equilibrium while monitoring the low-energy physics in the terahertz (THz) spectral range. This part of the electromagnetic spectrum is essential to understanding many aspects …
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Nonlinear terahertz spectroscopy of electronic and vibrational responses in condensed matter systems
… I describe experiments utilizing high-field terahertz (THz) pulses to initiate nonlinear responses in several classes of materials. We have developed several methods for interrogating the nonlinear THz response of materials including collinear and noncollinear THz-pump/THz-probe spectroscopy, …
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Investigating Hydration and Dynamics of Biomolecules in Solutions using High Precision Terahertz Spectroscopy
… give rise to absorption in the megahertz-to-terahertz frequencies. However, the strong absorption of water in this frequency range leads to a significant challenge in obtaining terahertz dielectric spectra of aqueous biomolecular solutions. In response, I have employed a high sensitivity …
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Terahertz spectroscopy to explore the role of vibrational dynamics in systems with varying structural order and disorder
… and this thesis investigates these points using terahertz time-domain spectroscopy (THz-TDS). Glycerol is commonly used to protect proteins during cryo-preservation and its interactions with small amounts of water are important to understand. The onset of molecular mobility, as measured by the …
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Studies of Protein-Protein and Protein-Water Interactions by Small Angle X-Ray Scattering, Terahertz Spectroscopy, ASMOS, And Computer Simulation
… algorithm. Secondly, we report that terahertz spectroscopy directly probes hydration dynamics around proteins and determines the size of the dynamical hydration shell. We also present the sequence and pH-dependence of the hydration shell and the effect of the hydrophobicity. On the …
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Elucidating the Electronic Origins of Intermolecular Forces in Crystalline Solids
… Furthermore, experimental X-ray diffraction and terahertz spectroscopy were both utilized because they are able to broadly probe the potential energy surfaces of molecular crystals, enhancing the theoretical data. Combining DFT calculations with experimental measurements enabled in-depth studies …
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