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 21 for “"THz imaging"”.
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THz imaging and microscopy, a multiplexed near-field TeraHertz microscope
None of the THz imaging techniques developed to date, permits high spatial resolution spectroscopic imaging at fast acquisition rates. In the classical THz sub-wavelength imaging with a single aperture, the image is composed by mechanically scanning the sample against a single sub-wavelength …
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Compact spectroscopic terahertz imaging solutions using GaAs/AlGaAs and InGaAs semiconductor nanostructures /
… 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 that under …
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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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Antennas for Terahertz Applications: Focal Plane Arrays and On-chip Non-contact Measurement Probes
The terahertz (THz) band provides unique sensing opportunities that enable several important applications such as biomedical imaging, remote non-destructive inspection of packaged goods, and security screening. THz waves can penetrate most materials and can provide unique spectral information in …
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Time frequency analysis techniques in terahertz pulsed imaging
Terahertz (THz) radiation is abundant in the natural world yet very hard to harness in the laboratory. Forming the boundary between `radio' and `light', the so called "terahertz gap" results from the failure of optical techniques to operate below a few hundred terahertz, and likewise the failure of …
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Room-Temperature Terahertz Detection Based on Graphene and Plasmonic Antenna Arrays
Terahertz (THz) radiation has become increasingly important in many scientific and commercial fields in recent years. It possesses many remarkable features resulting in an increased use of THz radiation for various applications, like biomedical imaging, security screening, and industrial quality …
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Developments in THz Polaritonics: Towards Integrated Nonlinear THz Spectroscopy
The terahertz (THz) polaritonics platform is a compact, waveguide-based platform for the generation, manipulation, and detection of THz waves. The platform uses thin (<100 μm) lithium niobate (LiNbO₃, LN) and lithium tantalate (LiTaO₃, LT) slabs, which can be patterned to control THz propagation. …
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Terahertz imaging arrays for room temperature operation summary of doctoral thesis /
This work intends to create optimized for THz range compact arrays of InGaAs bow-tie type sensors and to explore the possibilities of their applications. Depending on the simulated different metallic area resonances, new optimum InGaAs bow-tie shape designs for THz frequency range were created. …
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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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Developments in time-resolved ultrafast imaging and spectroscopy at terahertz frequencies
… femtosecond lasers, the field of terahertz (THz) spectroscopy was stagnated by the lack of both high power THz sources and sensitive THz detectors. Over the past few years, it has become more 'routine' to generate and detect THz radiation between 0.1-10 THz, but there remains much room for …
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Theory of terahertz intervalence band polaritons and antipolaritons.
… investigation of the interaction of terahertz (THz) radiation with intersubband excitations in microcavities leading to THz polaritons and antipolaritons. The approach is based on the dielectric function formalism. The dielectric constant is derived from an optical susceptibility evaluated with …
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Improving Computation for Hierarchical Bayesian Spatial Gaussian Mixture Models with Application to the Analysis of THz image of Breast Tumor
… in breast cancer margin assessment using THz imaging technology. In particular, the Bayesian estimate of uncertainty in the posterior probability from the spatial GMM shows promise in addressing the primary clinical question of determining the cancerous tumor margins. </p>
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Development of correction algorithm for pulsed terahertz computed tomography (THz-CT)
… been a considerable improvement in Terahertz (THz) science, technology, and imaging. In particular, the technique of 3-D computed tomography has been adapted to the THz range. However, it has been widely recognized that a fundamental limitation to THz computed tomography imaging is the …
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High Angular Resolution Beam Steering Terahertz Antenna Arrays for Imaging Applications
… technology for many applications, including imaging, radar, communications and other sensing applications due to bandwidth availability, penetration of dielectric materials, and short wavelength, enabling smaller structures. There is particular application in automotive radar imaging, where a …
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Optoelektroniniai terahercinio dažnių diapazono komponentai iš puslaidininkių su giliais centrais /
… on investigation of new material suitable for THz components activated with longer wavelength (1 and 1.55 μm) laser radiation. Dynamics of photoexcited electrons was investigated from the optically induced THz absorption of LTG GaAs layers grown on AlAs/GaAs Bragg mirror and annealed at …
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Terahertz optoelectronics components of semiconductor materials with deep defects /
… on investigation of new material suitable for THz components activated with longer wavelength (1 and 1.55 μm) laser radiation. Dynamics of photoexcited electrons was investigated from the optically induced THz absorption of LTG GaAs layers grown on AlAs/GaAs Bragg mirror and annealed at …
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THz Radiation Detection Based on CMOS Technology
The Terahertz (THz) band of the electromagnetic spectrum, also defined as sub-millimeter waves, covers the frequency range from 300 GHz to 10 THz. There are several unique characteristics of the radiation in this frequency range such as the non-ionizing nature, since the associated power is low and …
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Novel Applications of Terahertz Quantum Cascade Lasers: Gas Spectroscopy, Active Control & Nearfield Imaging
Since the advent of Terahertz (THz) quantum cascade lasers (QCLs) in 2002, they have seen significant improvement in output power, operating temperature, and spectral coverage as well as having been widely applied to astronomical applications, imaging, and spectroscopy because of their high output …
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Broadband Terahertz Signal Generation and Radiation Based on Direct Digital-to-Impulse Radiating Arrays in Silicon
Broadband terahertz (THz) signal generation and radiation has unique applications in 3-D hyper-spectral imaging, molecular sensing, and high-speed wireless communication. THz waves interact with the rotational and vibrational transitions of molecules with applications in material detection and …
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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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