Sökning: "terahertz sources."

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden terahertz sources..

  1. 1. Photonic terahertz-wave generation, radiation and quasioptical integration

    Författare :Biddut Kumar Banik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor device modelling; semiconductor diodes; III-V semiconductors; Catadioptric lens; imaging; dipole antennas; slot antennas; lens antennas; semiconductor heterojunctions; dielectric loaded antennas; optical mixers; photomixers; near-field imaging; computer aided engineering; indium compounds; millimetre wave imaging; near-field optics; submillimeter wave generation; photodiodes; terahertz sources; millimetre wave generation; submillimetre wave integrated circuits; microwave imaging; uni-travelling-carrier photodiodes;

    Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER

  3. 2. Photonic THz Generation and Quasioptical Integration for Imaging Applications

    Författare :Biddut Kumar Banik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nondestructive evaluation; semiconductor device modelling; uni-travelling-carrier photodiodes; millimetre wave and submillimetre wave generation; III-V semiconductors; photomixers; terahertz sources.; catadioptric lens; microwave imaging; dielectric loaded antennas; terahertz imaging; lens antennas; millimetre wave and submillimetre wave imaging;

    Sammanfattning : This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequencyrange. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. LÄS MER

  4. 3. Phase retrieval method for quantitative terahertz spectroscopy in reflection geometry

    Författare :Kasturie Jatkar; Stefano Bonetti; Magnus Berntsen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Terahertz; reflection; THz spectroscopy; InSb; Physics; fysik;

    Sammanfattning : Terahertz time-domain spectroscopy (THz-TDS) is a reliable technique used for studying the complex optical properties of materials. Its frequency range makes it suitable for detecting low-energy collective excitations such as phonons, magnons, and plasmons. THz-TDS in transmission geometry has gained much attention over the years. LÄS MER

  5. 4. Planar-Goubau-line components for terahertz applications

    Författare :Juan Cabello Sánchez; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; planar Goubau line; Through-Reflect-Line TRL calibration; stopband filter; on-wafer measurements; vector network analyzers VNA ; silicon membrane; power divider; Impedance-matched load; terahertz spectroscopy; microfluidic channels;

    Sammanfattning : Terahertz-wave technology has a broad range of applications, including radio astronomy, telecommunications, security, medical applications, pharmaceutical quality control, and biological sensing. However, the sources, detectors, and components are less efficient at this frequency band due to parasitic effects and increased total losses, which hinder the performance of terahertz systems. LÄS MER

  7. 5. Design and characterisation of terahertz Schottky diode harmonic mixers

    Författare :Divya Jayasankar; RISE Research Institutes of Sweden; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Schottky diodes; Phase locking; Harmonic mixers; Heterodyne receivers; Terahertz electronics; Frequency stabilisation; Frequency converters;

    Sammanfattning : Efficient, compact, and reliable terahertz frequency converters preferably operating at ambient temperature are crucial for stabilising far-infrared optical sources. This thesis focuses on the design and characterisation of terahertz Schottky diode harmonic mixers for frequency stabilisation of quantum-cascade lasers. LÄS MER