Sökning: "terahertz"

Visar resultat 1 - 5 av 67 avhandlingar innehållade ordet terahertz.

1. 1. Dynamical Analysis of Terahertz Quantum Cascade Lasers

   Författare :Denizhan Ekin Önder; NanoLund: Centre for Nanoscience; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Terahertz; quantum cascade lasers; electric field domains; chaos; simulation; Fysicumarkivet A:2023:Önder;

   Sammanfattning : This thesis focuses on various aspects in terahertz quantum cascade lasers such as high temperature performances, electrical instabilities and chaos. In the first part of the thesis, an introduction to the topic and the non equilibrium Green's function package applied is given with particular emphasise on the inhomogeneous domain model and the chaos theory. LÄS MER

3. 2. 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

4. 3. 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

5. 4. 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

7. 5. Self-Switching Diodes for Zero-Bias Terahertz Detection

   Författare :Andreas Westlund; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; self-switching diode; noise-equivalent power; SSD; graphene; zero-bias; InAs; InGaAs; terahertz; detector;

   Sammanfattning : The self-switching diode (SSD) has been investigated as a potential terahertz detector in recent years. The SSD accomplishes a non-linear current-voltage relation through a field-effect, which enables detection at zero bias from microwave up to terahertz frequencies. In this work, SSDs were realised in two new materials; InAs and graphene. LÄS MER