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Hot-electron bolometers are fast and low noise radiation detectors which can be used for many different applications. The aim of this work was to optimize the fabrication process of hot-electron bolometers and gain a deeper understanding of the underlying processes. To achieve this, the fabrication of the superconducting thin films was optimized and the superconducting properties of the films were analyzed. Detectors fabricated using the results showed a record value for the noise temperature.

noise temperature --- superconductivity --- THz detector --- optimization

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Breast cancer is the most common form of cancer affecting women in Europe. Tumours related to this cancer can be extracted through lumpectomy. During this surgery, the tumour and a margin of healthy tissues are extracted. The characterisation of this margin is done by histology but the results that give information on the probability for recurrence takes several hours to a day. To decrease the time needed for margin characterisation, medical imaging can be used. In this field, terahertz (THz) imaging appears promising due to its low price, low volume and because it is non-ionising.

This master thesis is about the application of THz imaging in margin characterisation during lumpectomies. More specifically, it deals with the influence of pressure on fresh biological tissues. To quantify the effects of pressure, experiments on pork lean meat and fat have been carried out with the TeraPulse 4000 machine developed by TeraView. During these experiments, pressure was monitored with a measurement system using force sensing resistors (FSRs) placed between two polytetrafluoroethylene (PTFE) plates. The measured voltages related to the FSRs values variations were recorded with an ArduinoTM and an application developed in C#. The data acquired by the TeraPulse 4000 were then analysed with MatLab. Moreover, the optical properties of the sample were computed when it was imaged in transmission mode. Three experiments have been carried out in this study: THz imaging of a piece of brass in reflection and transmission modes, THz imaging of meat and fat in transmission mode, and THz imaging of meat and fat in reflection mode. The results of these experiments showed that several other parameters in addition to pressure influenced the samples THz imaging. As a consequence, the influence of pressure alone was not distinguishable. However, the experiments showed that monitoring of pressure is important in biomedical applications to improve the sample adherence to its holder when imaging in reflection mode which is more used in this field than transmission one.

THz imaging --- Pressure --- Fresh animal tissues --- TeraPulse 4000 --- Brest cancer --- Ingénierie, informatique & technologie > Multidisciplinaire, généralités & autres

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The THz region of the electromagnetic spectrum is a frontier research area involving application of many disciplines, from outdoor to indoor communications, security, drug detection, biometrics, food quality control, agriculture, medicine, semiconductors, and air pollution. THz research is highly demanding in term of sources with high power and time resolution, detectors, and new spectrometer systems. Many open questions still exist regarding working at THz frequencies; many materials exhibit unusual or exotic properties in the THz domain, and researchers need new methodologies to exploit these opportunities. This book contains original papers dealing with emerging applications, new devices, sources and detectors, and materials with advanced properties for applications in biomedicine, cultural heritage, technology, and space.

terahertz --- free electron laser --- energy recovery --- THz spectroscopy --- free-electron-lasers --- nonlinear optics --- THz --- waveguide spectroscopy --- coating materials --- particle accelerators --- leaky-wave antennas --- metasurface --- liquid crystals --- graphene --- FEL --- copper --- damage --- surface --- coherent synchrotron radiation --- low alpha --- cross-correlation --- pump-probe --- terahertz spectroscopy --- terahertz time-domain spectroscopy --- terahertz pulsed imaging --- near-field imaging --- biomedical imaging --- cancer diagnosis --- endoscopy --- infrared analysis --- microspectroscopy --- cultural heritage --- synchrotron radiation --- niobium --- proximity effects --- superconductivity --- detectors --- Vortex dynamics --- bunch length --- linac --- far infrared --- spectroscopy --- imaging --- THz source --- high-brightness electron beams --- laser comb technique --- optical indices --- nonlinear effects --- optical rectification --- organic crystals --- HMQ-TMS --- waveguides --- THz detector --- THz imaging

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Don d'André Vander Vorst

Fysica --- Physique --- Circuits électroniques --- Micro-ondes --- Télécommunications --- Bran --- Organe de transmission --- Transmissions --- Microwave radiation --- Communication --- Technique de communication --- communication technology --- 537.8.029 --- 621.3.029.6 --- Frequency ranges of electromagnetic waves --- 1 x 10 -4" m. Ultra-short waves"">Frequencies from 30 MHz to < 3 THz. Wavelengths from 1 x 10 1" to > 1 x 10 -4" m. Ultra-short waves --- 1 x 10^-4" m. Ultra-short waves"">621.3.029.6 Frequencies from 30 MHz to < 3 THz. Wavelengths from 1 x 10^1" to > 1 x 10^-4" m. Ultra-short waves --- 1 x 10^-4" m. Ultra-short waves"">Frequencies from 30 MHz to < 3 THz. Wavelengths from 1 x 10^1" to > 1 x 10^-4" m. Ultra-short waves --- 537.8.029 Frequency ranges of electromagnetic waves --- Circuits électroniques --- Télécommunications --- Électronique

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The Terahertz frequency range (0.1 – 10)THz has demonstrated to provide many opportunities in prominent research fields such as high-speed communications, biomedicine, sensing, and imaging. This spectral range, lying between electronics and photonics, has been historically known as “terahertz gap” because of the lack of experimental as well as fabrication technologies. However, many efforts are now being carried out worldwide in order improve technology working at this frequency range. This book represents a mechanism to highlight some of the work being done within this range of the electromagnetic spectrum. The topics covered include non-destructive testing, teraherz imaging and sensing, among others.

Research & information: general --- W band --- Schottky Diode Detectors --- ZBD modeling --- wire bonding --- flip-chip --- Terahertz radar --- radar cross-section --- signal-to-noise ratio --- adaptive range gates --- cascaded doubler --- quadrupler --- Schottky varactor --- hybrid integrated circuit --- terahertz spectroscopy --- optical delay line --- correction --- optical encoder --- terahertz spectra --- terahertz metrology --- bias --- sub-harmonic mixer --- anti-series --- Schottky diode --- conversion loss --- terahertz wave generation --- InGaAs --- molecular beam epitaxy --- time-domain spectroscopy --- photoconductive antenna --- open stone relics --- hollowing --- weathered --- preservation of cultural heritage --- THz-TDS --- rubber --- vulcanization --- silica dispersion --- terahertz imaging --- light field imaging --- synthetic aperture imaging --- image distortion --- resolving power --- THz detector --- rectangular inset-feed patch antenna --- catadioptric horn-like lens --- CMOS process --- resonances --- periodic waveguides --- reflection phases --- topological properties --- oscillator --- THz --- high output power --- CMOS --- terahertz waves --- honeycomb sandwiches --- foreign materials --- time-of-flight --- electric field