Sökning: "Polarization measurements"

Visar resultat 1 - 5 av 147 avhandlingar innehållade orden Polarization measurements.

  1. 1. Photospheric emission from structured, relativistic jets : applications to gamma-ray burst spectra and polarization

    Författare :Christoffer Lundman; Felix Ryde; Andrei Beloborodov; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma-ray bursts; photospheric emission; radiative processes; polarization; special relativity;

    Sammanfattning : The radiative mechanism responsible for the prompt gamma-ray burst (GRB) emission remains elusive. For the last decade, optically thin synchrotron emission from shocks internal to the GRB jet appeared to be the most plausible explanation. LÄS MER

  3. 2. Mode and Polarization Control in VCSELs using Surface Structures

    Författare :Åsa Haglund; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; single mode; dynamics; surface relief; Semiconductor laser; polarization; vertical-cavity surface-emitting laser; sub-wavelength grating; fabrication;

    Sammanfattning : The vertical-cavity surface-emitting laser (VCSEL) is a novel, low-cost light source with many attractive performance characteristics, such as low operating current, circular output beam, and high modulation bandwidth at low currents. This together with its easy integration into two-dimensional arrays has made it an established transmitter in short-distance single and parallel fiber-optical links, and new applications are continuously arising. LÄS MER

  4. 3. Theory and Applications of Tri-Axial Electromagnetic Field Measurements

    Författare :Roger Karlsson; Bo Thid'e; Tobia Carozzi; Gudmund Wannberg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; polarisation; polarization; Stokes parameters; antenna; radio waves; whistler wave; SEE; direction-finding; statistics; Poynting theorem; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : Polarisation, which was first studied in optics, is a fundamental property of all electromagnetic fields. A convenient way to describe the polarisation of two dimensional electromagnetic fields is given by the Stokes parameters. This thesis deals with different aspects of wave polarisation and electromagnetic field measurements. LÄS MER

  5. 4. Multi-Level Lossless Phase Modulation in Liquid Crystals for High-Speed Spatial Light Modulators

    Författare :David Engström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; phase measurements; polarization; phase modulation; beam steering; Spatial light modulators; diffractive optics; ferroelectric liquid crystals;

    Sammanfattning : The spatial light modulator (SLM) is a compact device that enables highly precise control of light propagation with low drive voltages and no moving parts. By imposing a certain phase modulation onto the incident lightwave, functions such as multi-beam steering, beam shaping, and air turbulence corrections can be achieved in realtime. LÄS MER

  7. 5. Design of Functional Structures and Measurement Techniques for Electromagnetic Waves

    Författare :Johan Lundgren; Teoretisk elektroteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; functional structures; frequency selective structures; polarization selectivity; metasurface; near-field measurements; antenna measurements; scattering measurement; power density; random media;

    Sammanfattning : Electromagnetic fields exist all around us. Through evolution, nature has developed tools to interact and use these fields, where our eyes are a spectacular example. Humans have a long history of developing structures and objects of their own to alter and interact with these fields. LÄS MER