Sökning: "terahertz imaging"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden terahertz imaging.

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. Silicon micromachined waveguide components for terahertz systems

   Författare :Bernhard Beuerle; Joachim Oberhammer; Umer Shah; Kamal Sarabandi; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; micromachining; waveguide; terahertz; deep reactive ion etching; silicon on insulator; on-wafer characterization; InP; SiGe; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis presents silicon micromachined waveguide components for sub-terahertz and terahertz (THz) systems fabricated by deep reactive ion etching (DRIE). Historically the main driving force for the development of THz systems has been space-based scientific instruments for astrophysics, planetary and Earth science missions. LÄS MER

5. 4. Exploiting the Terahertz Spectrum with Silicon Micromachining : Waveguide Components, Systems and Metrology

   Författare :James Campion; Joachim Oberhammer; Umer Shah; Robert M. Weikle II; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Terahertz; Silicon Micromachining; Waveguide; Waveguide System; Metrology; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : The terahertz spectrum (300 GHz - 3 THz) represents the final frontier for modern electronic and optical systems, wherein few low-cost, volume-manufacturable solutions exist. THz frequencies are of great scientific and commercial interest, with applications as diverse as radio astronomy, sensing and imaging and wireless communications. LÄS MER

7. 5. Ultrafast spin dynamics at the nanoscale : using coherent X-ray and terahertz radiation

   Författare :Nanna Zhou Hagström; Stefano Bonetti; Stefan Eisebitt; Ferran Macià Bros; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; XFEL; small-angle X-ray scattering; X-ray holography; ultrafast magnetism; symmetry-breaking; magnetic domains; terahertz; magnetic field enhancement; metamaterial; time-resolved magneto-optical microscope; Physics; fysik;

   Sammanfattning : The field of ultrafast magnetism is driven by the growing need for faster and more efficient magnetic data storage, which comprises the vast majority of the digital information worldwide. However, after more than two decades of intense research, the understanding of the fundamental physical processes governing the transfer of angular momentum necessary for magnetic switching, is still lacking, partially hampered by the appropriate experimental tools. LÄS MER