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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 28 for “"Terahertz time domain spectroscopy"”.
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Experimental and Numerical Investigations into Terahertz Time-Domain Spectroscopy
… results that benchmark a state-of-the-art terahertz time-domain spectrometer. We begin by describing the theory behind the nonlinear optical mechanisms through which we generate and detect short pulses of THz radiation. Based on a coherent electro-optic detection scheme, our measurements …
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Terahertz Time-Domain Spectroscopy of Low-Dimensional Materials and Photonic Structures
<p>Terahertz (THz), the frequency region that bridges the gap between the radio and optical frequencies in the electromagnetic spectrum, is of both scientific and technological importance. Its broad applications, however, have been limited by the availability of bright sources and sensitive …
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Characterizing and mitigating scattering effects in terahertz time domain spectroscopy measurements.
Terahertz research has came a long way since its inception in the mid 1980s when the first pulsed THz emission was reported using electro-optic sampling. With rapid advent in THz generation and detection techniques, research in terahertz time-domain spectroscopy (THz-TDS) has progressed to such a …
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Temperature-dependent Terahertz Time-domain Spectroscopy as a Tool to Assess the Crystallisation Tendencies of Amorphous Drug-Polymer Systems
… of amorphous drugs to recrystallise over time. This thesis explores the use of temperature-dependent terahertz time-domain spectroscopy (THz-TDS) as a sensitive, non-destructive tool to probe molecular mobility and predict the physical stability of amorphous drug-polymer systems. …
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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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Software implementation of a terahertz imaging and spectroscopy platform
A terahertz imaging system was built from commercially available hardware whose functionality was integrated through home-made software with the goal of building a terahertz imaging platform for which other terahertz technologies would be born out of. The core of the system is based on terahertz …
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CHARACTERIZATION OF CRYSTALLINE PIGMENTS WITH LOW-FREQUENCY VIBRATIONAL SPECTROSCOPY AND SOLID-STATE DENSITY FUNCTIONAL THEORY
… of their non-ionizing nature, rapid acquisition times, and safety. Unfortunately, the majority of these methods have difficulty distinguishing between pigments with similar chemical and physical properties. Recent advancements in instrument technology have increased the broader availability of …
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Phononenprozesse und Ladungsträgerdynamik in Halbleitern
… Eigenschaften von Halbleitern mit Hilfe der Terahertz Time-Domain Spectroscopy (THz-TDS) experimentell untersucht. Der dabei gemessene Brechungsindex und Absorptionskoeffzient im Ferninfrarotbereich ist sowohl mit der Kristalldynamik als auch mit der Ladungsträgerdynamik des Halbleiters …
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Computational Methodologies for the Simulation and Analysis of Low-frequency Vibrations in Molecular Crystals
… can become readily apparent. In this work, terahertz time-domain spectroscopy and low-frequency Raman spectroscopy are used as benchmark experimental targets to develop computational methodologies for simulating and analyzing the lattice vibrations of molecular crystals such as torsions and …
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EXPERIMENTAL AND COMPUTATIONAL ANALYSIS OF RELATIVE ENERGETIC STABILITIES OF CRYSTALLINE ANHYDROUS POLYMORPHS AND PSEUDOPOLYMORPHS
… density functional theory (ss-DFT) and terahertz time-domain spectroscopy (THz-TDS). Terahertz spectroscopy of the lattice vibrations offers a sensitive probe of solid-state interactions and serves as a rigorous benchmark for testing the quality of the applied theoretical methods. …
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Ultrafast Spin-Charge Conversion Schemes in Magnets: THz Time Domain Spectroscopy Study
… unprecedented ultrafast speeds, corresponding to Terahertz frequencies. The crucial requirement for implementing spins into electronic systems is the efficient spin-charge conversion at ultrafast speeds. Therefore, the research requires experimental tools operating at the desired timescales. An …
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Terahertz Methods for Investigating the Liquid Transport Characteristics in Porous Media
… and heterogenous catalysis. In this thesis, the terahertz methods, i.e. terahertz time-domain spectroscopy (THz-TDS) and terahertz pulsed imaging (TPI), were used as promising techniques to quantify the impact of the microstructure characteristics and formulation on the liquid transport process …
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Broadband terahertz photonics
… as mature semiconductor sources of light in the terahertz range, the frequency range spanning 1 to 10 THz. Though technological development has pushed their operating temperatures up to 200 Kelvin and their power levels up to Watt-level, they have remained unsuitable for many applications as a …
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Terahertz metamaterials for sensing and detection
… of metamaterials targeted for operation at terahertz frequencies was investigated including split-ring resonators, perfect absorbers, and flexible absorbers. The devices were designed through simulation by finite element method commercial software and fabricated by photolithographic lift-off …
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Investigating the Variations in Molecular Mobility within Amorphous Formulations using Terahertz Spectroscopy
… which leads 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 …
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Investigating Controlled Release Pulmonary Drug Delivery Systems
… could be improved by reducing the number of times drugs need to be administered. In this study, two controlled pulmonary drug delivery systems for drugs of different solubilities were investigated and they were characterised for their viability as effective controlled release pulmonary drug …
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Structural Dynamics of Amorphous Solid-State Macromolecular Materials at Terahertz Frequencies
… Solid-State Macromolecular Materials at Terahertz Frequencies Talia Amira Shmool The aim of this thesis is to investigate the ability of terahertz time-domain spectroscopy (THz-TDS) to study complex amorphous solid-state systems. THz-TDS is a vibrational optical spectroscopy technique …
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Investigating the Properties and Lattice Vibrations of Ordered and Disordered Crystalline Materials
… the techniques of low-frequency vibrational spectroscopy by means of terahertz time-domain spectroscopy (THz-TDS) were combined with density functional theory (DFT) simulations to investigate the role and effect of disorder for small organic molecular materials including drug molecules as …
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