Sökning: "Geometrical optics"

Visar resultat 1 - 5 av 36 avhandlingar innehållade orden Geometrical optics.

  1. 1. Manipulation of Light with Transformation Optics

    Författare :Wei Yan; Min Qiu; Niels Asger Mortensen; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transformation optics; Maxwell’s equations; invisibility cloaks; compensated bilayer; perfect imaging; optical illusion; nihility media; α media; Optics; Optik;

    Sammanfattning : Transformation optics, a recently booming area, provides people a new approach to design optical devices for manipulating light. With transformation optics, a lot of novel optical devices are proposed, such as invisibility cloaks, optical wormholes, optical black holes, illusion devices. LÄS MER

  2. 2. Opening New Radio Windows and Bending Twisted Beams

    Författare :Erik Nordblad; Thomas B. Leyser; Kristof Stasiewicz; Vladimir Pavlenko; Paul A. Bernhardt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Orbital angular momentum; Hall effect; Nonparaxial beam; Geometrical optics; High frequency radio waves; Ray tracing; Magnetic zenith effect; Ionospheric irregularities; Wave propagation; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : In ground based high frequency (HF) radio pumping experiments, absorption of ordinary (O) mode pump waves energises the ionospheric plasma, producing optical emissions and other effects. Pump-induced or natural kilometre-scale field-aligned density depletions are believed to play a role in self-focussing phenomena such as the magnetic zenith (MZ) effect, i. LÄS MER

  3. 3. Adaptive Optics in Integrated Modeling of Telescopes

    Författare :Anita Enmark; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; extremely large telescope; adaptive optics; Integrated model;

    Sammanfattning : This thesis present the implementation of a modular adaptive optics (AO) model, as part of an integrated model of extremely large telescopes (ELTs). The purpose of the project has been to establish knowledge within integrated modeling, with emphasis on adaptive optics. LÄS MER

  4. 4. Fish Lenses : Anatomy and Optics

    Författare :Tomasz M Kozłowski; Funktionell zoologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Plasticity; Development; Cellular structure; Lens fiber cells; Modeling; Laser Scanning; Schlieren photography; Fast Fourier Transform FFT ;

    Sammanfattning : I have investigated some of the biological regulatory mechanisms governing the development of crystalline lenses. I used fish as model animals because they possess optically interesting lenses, while the geometrical simplicity of fish lenses allows for studies that are difficult or impossible with the lenses of other animals. LÄS MER

  5. 5. Spectral Mammography with X-Ray Optics and a Photon-Counting Detector

    Författare :Erik Fredenberg; Mats Danielsson; Björn Cederström; Jeffrey H. Siewerdsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; mammography; x-ray optics; photon counting; spectral shaping; spectral imaging; collimation; radiation dose; signal-to-noise ratio; quantum noise; anatomical noise; spatial resolution; x-ray flux; ; TECHNOLOGY; TEKNIKVETENSKAP; Engineering physics; Teknisk fysik; Optical physics; Optisk fysik; Other engineering physics; Övrig teknisk fysik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik; Medical engineering; Medicinsk teknik; Radiological research; Radiologisk forskning;

    Sammanfattning : Early detection is vital to successfully treating breast cancer, and mammography screening is the most efficient and wide-spread method to reach this goal. Imaging low-contrast targets, while minimizing the radiation exposure to a large population is, however, a major challenge. LÄS MER