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 25 for “"THz-TDS"”.
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Structural Dynamics of Amorphous Solid-State Macromolecular Materials at Terahertz Frequencies
… ability of terahertz time-domain spectroscopy (THz-TDS) to study complex amorphous solid-state systems. THz-TDS is a vibrational optical spectroscopy technique which can probe the intermolecular librations and vibrations of materials. Previous work has explored the use of THz-TDS in probing …
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Terahertz Time Domain Spectroscopy of Anisotropic Systems: techniques, analysis and applications
… method of terahertz time domain spectroscopy (THz-TDS) allows determination of the broadband electromagnetic response of materials over a typical spectral region of 0.3 to 3 THz. Past work in this field has generally been dominated by the investigation of isotropic materials and the significant …
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Characterizing and mitigating scattering effects in terahertz time domain spectroscopy measurements.
… 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 great extent that terahertz is finding potential …
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Investigating the Variations in Molecular Mobility within Amorphous Formulations using Terahertz Spectroscopy
… 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 polymer-water binary system, representing the …
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Ultrafast Spin-Charge Conversion Schemes in Magnets: THz Time Domain Spectroscopy Study
… is Terahertz time domain spectroscopy (THz TDS). In this thesis, we use THz TDS to investigate the routes by which the spin ordering, spin dynamics, and spin currents can lead to the generation of ultrafast charge currents. We study a variety of magnetic systems to experimentally …
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CHARACTERIZATION OF CRYSTALLINE PIGMENTS WITH LOW-FREQUENCY VIBRATIONAL SPECTROSCOPY AND SOLID-STATE DENSITY FUNCTIONAL THEORY
… of terahertz time-domain spectroscopy (THz-TDS) and low-frequency Raman spectroscopy (LFRS). In this work, the capabilities of THz-TDS and LFRS for identification and characterization of historic and modern pigments were evaluated. These experimental studies were supported with …
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Broadband THz time-domain spectroscopy of biomolecules : a comprehensive study of the dielectric properties of biomaterials in the far-infrared
Since the introduction of THz-time-domain spectroscopy (THz-TDS) in the late 1980's, the technique, based on the generation and detection of subpicosecond terahertz pulses, has found widespread use as a simple and versatile experiment technique for obtaining the low frequency response of gases, …
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Semiconductor nanowires: towards enhanced terahertz sources
… electromagnetic radiation in terahertz (THz) frequency region by utilizing semiconductor nanowires due to advantages attributed to their one-dimensional structure, and also studying materials properties by adopting ultrafast THz time-domain spectroscopy (THz-TDS). In order to achieve …
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EVALUATION OF TERAHERTZ TECHNOLOGY TO DETERMINE CHARACTERISTICS AND CONTAMINANTS IN ENGINE OIL
… by using terahertz time-domain spectroscopy (THz-TDS). The first experiment was classifying gasoline engine oils of various viscosities by using THz-TDS. The range of 0.5–2.0 THz was evaluated for distinguishing among gasoline engine oils of three different grades (SAE 5W-20, 10W-40, and …
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Temperature-dependent Terahertz Time-domain Spectroscopy as a Tool to Assess the Crystallisation Tendencies of Amorphous Drug-Polymer Systems
… 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. Specifically, the work investigates how molecular properties – such as hydrogen bonding capacity and …
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Terahertz spectroscopy to explore the role of vibrational dynamics in systems with varying structural order and disorder
… 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 infrared active dipoles in …
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Characteristics of nanocomposites and semiconductor heterostructure wafers using THz spectroscopy
All optical, THz-Time Domain Spectroscopic (THz-TDS) methods were employed towards determining the electrical characteristics of Single Walled Carbon Nanotubes, Ion Implanted Si nanoclusters and Si_{1-x}Ge_x HFO_2, SiO_2 on p-type Si wafers. For the nanoscale composite materials, Visible Pump/THz …
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Terahertz Spectroscopy of Topological Insulators and other 2-Dimensional 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 the various optical and electronic …
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Investigating the Properties and Lattice Vibrations of Ordered and Disordered Crystalline Materials
… 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 well as other emerging materials. Terahertz radiation is located …
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PHARMACEUTICAL INSTRUMENTATION DEVELOPMENT FOR IN-PROCESS MONITORING OF FREEZE-DRYING CYCLES
… the chamber in the space above the vial using a THz and laser absorption approach from which ice interface temperature can be determined. The second is to establish the use of impedance spectroscopy for the in-vial determination of the phase behaviour of surrogate formulations of mannitol and …
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Terahertz response of microfluidic-jetted fabricated 3D flexible metamaterials
… techniques to construct metamaterials in THz range via a material deposition system. The metamaterials are fabricated by stacking alternative layers with conventional designs such as single ring- split ring resonators (SRR) and microstrips to form a 3D metamaterial structure. Conductive …
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Phononenprozesse und Ladungsträgerdynamik in Halbleitern
… 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 verknüpft. Im ersten Teil der Arbeit …
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Modern spectroscopy on biological molecules : structure and bonding investigated by THz time-domain and transient phase-grating spectroscopy
Since the first freely propagating THz pulses have been used to conduct spectroscopic investigations in the far-IR, THz time-domain spectroscopy (THz-TDS) has evolved into a versatile tool for the study of a variety of different sample materials. However its application to the investigation of …
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EXPERIMENTAL AND COMPUTATIONAL ANALYSIS OF RELATIVE ENERGETIC STABILITIES OF CRYSTALLINE ANHYDROUS POLYMORPHS AND PSEUDOPOLYMORPHS
… (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. Vibrational simulations of different …
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Mode-locked surface emitting semiconductor lasers
… components. Radiation with a bandwidth of 0.8 THz has been generated using sub-500 fs pulses with an average power of 20 mW from a mode-locked VECSEL which contains InGaAs quantum wells and an LT-GaAs/InGaAs emitter/receiver antenna in a Terahertz Time Domain Spectrometer (THz-TDS) setup. The …
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