Sökning: "phase grating"

Visar resultat 1 - 5 av 41 avhandlingar innehållade orden phase grating.

1. 1. Laboratory X-Ray Phase-Contrast Imaging : Methods and Comparisons

   Författare :Tunhe Zhou; Anna Burvall; Hans M. Hertz; Tim Salditt; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray imaging; Phase-contrast; Liquid-metal-jet source; Propagation-based imaging; Grating-based imaging; Speckle-based imaging; Fysik; Physics;

   Sammanfattning : X-ray phase-contrast imaging has seen rapid development in recent decades due to its superior performance in imaging low-absorption objects, compared to traditional attenuation x-ray imaging. Having higher demand on coherence, x-ray phase-contrast imaging is performed mostly at synchrotrons. LÄS MER

3. 2. Fibre Bragg Grating Components for Filtering, Switching and Lasing

   Författare :Zhangwei Yu; Lars Thylén; Pierre-Yves Fonjallaz; Lin Zhang; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fibre Bragg grating; photosensitivity; apodization; chirp; phase-shift; microwave optical filtering; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Sammanfattning : Fibre Bragg gratings (FBGs) are key components for a vast number of applications in optical communication systems, microwave photonics systems, and optical sensors, etc. The main topic of this thesis is fibre Bragg grating fabrication and applications in direct microwave optical filtering, high speed switching and switchable dual-wavelength fibre lasers. LÄS MER

4. 3. Dynamic and Static Diffractive Optics - some Examples

   Författare :Björn Löfving; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; subwavelength grating; spatial light modulator; phase retrieval; diffractive optics; ferroelectric liquid crystal; analog-to-digital conversion; optical switch; feedback generated hologram;

   Sammanfattning : Diffractive optics is a modern branch of optics, that exploits microstructures to manipulate the propagation of light. Fast computers and the progress in manufacturing technique of microelectronics have made possible a rapid development of diffractive optics during the past 10 years. LÄS MER

5. 4. Optical properties and helicity in liquid crystals

   Författare :Anders Dahlgren; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; de Vries formula; smectic A*; smectic helix; Poincaré sphere; homeotropic alignment; chiral; light switch; birefringence; electroclinic; diffraction method; indicatrix; phase grating; helial pitch; snisotropy; liquid crystals; smectic C*; handedness; book-shelf geometry; Cano method; ferroelectric; biaxiality; dielectric tensor;

   Sammanfattning : .... LÄS MER

7. 5. Infrared Laser-Induced Grating Techniques for Diagnostics in Reactive Flows

   Författare :Dina Hot; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Laser diagnostics; infrared; laser-induced grating spectroscopy; degenerate four-wave mixing; flames; temperature; concentration; Fysicumarkivet A:2020:Hot;

   Sammanfattning : AbstractThe work presented in this thesis is mainly focused on the development andapplication of infrared laser-induced grating techniques in order to measure the gasphase temperature and species concentrations in reactive flows. The two techniquesused for this purpose are laser-induced grating spectroscopy (LIGS) and degeneratefour-wave mixing (DFWM). LÄS MER