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 86 for “"terahertz (THz)"”.
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A 2-D Scalable Third harmonic radiator at 291.3 GHz with -2 dBm of Radiated Power in 22 nm FinFET Technology
The Terahertz (THz) band exhibits potential for novel applications and improvements to existing systems such as spectroscopy, imaging, and high-speed communications. However, the lack of high-power sources at this frequency range hinders the wide-scale adoption of these technologies commercially. …
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THz Cryo-CMOS Link for Quantum Computing
In this thesis, a terahertz (THz) cryo-CMOS link for quantum computing and other cryogenic applications is designed. This THz wireless link can efficiently deliver the control signals and data between room temperature and cryogenic environment. Its operation allows for a small antenna aperture …
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Terahertz-field-induced nonlinearity in phonons, electrons and spins
… nonlinear material responses initiated by strong terahertz (THz) field excitation. I discuss two aspects of nonlinear THz spectroscopy in condensed-matter materials: developments of experimental THz capabilities and spectroscopy methods and their applications in investigating ultrafast nonlinear …
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Towards terahertz dual-comb spectroscopy based on quantum cascade lasers
In this thesis, terahertz (THz) laser frequency combs are improved and THz dual-comb spectroscopy method is demonstrated. To achieve better performance of THz quantum cascade laser (QCL) frequency combs, several broadband homogeneous and heterogeneous gain media are characterized, and corresponding …
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Terahertz waveguide spectroscopy of two-dimensional plasmons in GaAs
… been examined to some extent from microwave to terahertz (THz) frequencies, a fundamental understanding of the physical properties of 2DEGs in this range have by no means been mastered. To address this matter, this thesis focused on studying a fundamental, high-frequency collective excitation, …
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Two-dimensional terahertz rotational spectroscopy in the gas phase
… for decades, but its extension into the terahertz (THz) regime remains rare. In this thesis, I describe several experiments using two-dimensional terahertz rotational spectroscopy. Employing intense THz electromagnetic fields and the differential chopping technique, we have extended …
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Large-scale high-density terahertz radiator and receiver Arrays on silicon chips
Electromagnetic (EM) waves in the terahertz (THz) frequency range (usually deαned as from 10⁻¹ THz to 10¹ THz) have important applications in gas sensing, non-invasive imaging, short-range ultra-high-data-rate wireline/wireless communications. Historically, due to their speed limit, silicon-based …
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Efficient THz lasers and broadband amplifiers based on quantum cascade gain media
One of the most important applications for Terahertz (THz) quantum cascade (QC) lasers is to provide compact and powerful frequency-stabilized solid-state sources as local oscillators in heterodyne receivers for astronomical studies. The first part of the thesis is dedicated to the device cavity …
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Generation of high power single-cycle and multiple-cycle terahertz pulses
… and frequency-tunable multiple-cycle terahertz (THz) pulses pumped with near-infrared ultrashort optical pulses at 1 kHz and 10 Hz repetition rates. Single-cycle THz pulses with sub-picosecond duration and more than 50 pJ pulse energy, and multiple-cycle THz pulses with picosecond …
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Integrated diffractive optical elements for terahertz beam shaping and polarization control /
… control and enhanced transparency in the terahertz (THz) frequency range (0.1–1 THz). Utilizing semiconductor- and metal-based elements, the research introduces hybrid multi-phase Fresnel zone plate (H-MPZP) lenses with reduced structural complexity and enhanced focusing performance, high …
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Design, fabrication and characterization of terahertz quantum-well photodetectors
Terahertz (THz) photodetectors are important in the fully exploration and development of electromagnetic spectrum. However, a fast and sensitive THz photodetector ready for array integration is not available. A THz Quantum-well Photodetector (QWP) has the properties of being fast, sensitive, …
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PULSED THz GENERATION BASED ON PHOTOCONDUCTIVE ANTENNA FOR THz TIME-DOMAIN SPECTROSCOPY
Terahertz (THz) wave is defined as the region of the electromagnetic spectrum with frequencies ranging from 100 GHz to 10 THz. The THz technology has many potential applications. However, it was called the “THz gap” due to the lack of efficient generation of THz waves. Therefore, the development of …
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High field, high efficiency terahertz pulse generation by optical rectification
… of producing high intensity radiation in the terahertz (THz) spectral region by conventional electronics has stimulated interest in development of sources based on photonics. Optical rectification in lithium niobate is an attractive approach, because it supports high generation efficiencies, …
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Optically detected terahertz resonance spectroscopy of semiconductor nanostructures
… developed an ultracompact optically-detected terahertz resonance (ODTR) spectroscopy system, using quantum cascade lasers (QCLs). This system can be used for investigating various terahertz (THz) resonances in semiconductors. We use a THz QCL, of an appropriate frequency, operating in the …
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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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Electromagnetic modeling of terahertz quantum cascade laser waveguides and resonators
… waveguides and resonators used in terahertz (THz) quantum cascade lasers (QCLs) is presented. Simulations and analysis of two types were performed: two-dimensional waveguides, and two- and three-dimensional resonators. Both metal-metal and semi-insulating (SI) surface-plasmon …
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Compact spectroscopic terahertz imaging solutions using GaAs/AlGaAs and InGaAs semiconductor nanostructures /
… for room temperature compact spectroscopic terahertz (THz) imaging systems involving all basic components such as emitters, amplifiers, optics, and detectors. THz source based on p-i-n-i -type GaAs/AlGaAs heterostructure was experimentally investigated for the first time. It is demonstrated …
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Išorinio poveikio įtaka terahercų taikymams telekomunikacijose /
… need. One of the promising candidates is the Terahertz (THz) Band (100 GHz – 10 THz), but the THz waves are very vulnerable in the atmosphere. In this work, the possibilities and limitations of the THz wireless networks were examined in terms of the atmospheric attenuation, mostly rain …
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Impact of external effects on terahertz applications for telecommunications /
… need. One of the promising candidates is the Terahertz (THz) Band (100 GHz – 10 THz), but the THz waves are very vulnerable in the atmosphere. In this work, the possibilities and limitations of the THz wireless networks were examined in terms of the atmospheric attenuation, mostly rain …
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Study of propagation and detection methods of terahertz radiation for spectroscopy and imaging
The applications of terahertz (THz, 1 THz is 1012 cycles per second or 300 pm in wavelength) radiation are rapidly expanding. In particular, THz imaging is emerging as a powerful technique to spatially map a wide variety of objects with spectral features which are present for many materials in THz …
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