Sökning: "Ultra-short laser pulse"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden Ultra-short laser pulse.

1. 1. Ultrafast Magnetization Dynamics : Element-selective studies of magnetic alloys using ultra short XUV pulses

   Författare :Rameez Saeed Malik; Olof Karis; Uwe Bovensiepen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magnetization dynamics; magnetic alloys; HHG; ultrashort laser pulses; magneto-optical Kerr effect MOKE ; Gilbert damping; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : In this thesis, I investigate the ultrafast magnetization dynamics in 3d ferromagnets and their alloys with ultrashort laser pulses. The high harmonics generation (HHG) setup provides extreme-ultraviolet photons with energies 35-72 eV, which is the energy range where 3d metals have their M2,3 absorption edges. LÄS MER

3. 2. Electronic materials : growth and characterisation

   Författare :Michael A. Grishin; Ulf O. Karlsson; Massimo Sancrotti; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrophysics; Photoemission; Ultra-short laser pulse; Thin film; Laser deposition; InSb; InAs; GaSb; Ferroelectrics; Elektrofysik; Electrophysics; Elektrofysik;

   Sammanfattning : In this thesis the InSb(111), InAs(111) and GaSb(001) surfaces have been studied by means of time- and angle-resolved photoemission spectroscopy based upon the femtosecond laser system. The pump-and-probe technique allows to analyse both electron states in the valence band and normally unpopulated electron states above the valence band, which can be occupied by transiently excited carriers at the optically pumped surface. LÄS MER

4. 3. Extreme Electron Beams and Brilliant X-rays : Generation, Manipulation and Characterization of Relativistic Electron Beams for and from Plasma-Based Accelerators

   Författare :Jonas Björklund Svensson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; laser; plasma; wakefield; acceleration; accelerator; relativistic; electrons; x-rays; ultra-fast; betatron; laser-wakefield acceleration; plasma-wakefield acceleration; Fysicumarkivet A:2020:Björklund;

   Sammanfattning : This thesis is based on work done by the author on the development of plasma-based electron accelerators driven by ultra-intense laser pulses and dense electron bunches. Plasma based accelerators have several benefits, such as accelerating fields around 1000 times stronger than in “conventional” radio-frequency accelerators, which can allow for shrinking the overall footprint of the accelerator. LÄS MER

5. 4. Scaling and Gating Attosecond Pulse Generation

   Författare :Christoph Heyl; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Coherent imaging; Ultrafast electron dynamics; Single attosecond pulses; Attosecond pulse trains; XUV sources; High-order harmonic generation; XUV frequency combs; Fysicumarkivet A:2014:Heyl;

   Sammanfattning : High-order harmonic generation (HHG) provides the basis for attosecond light sources delivering coherent pulses in the extreme ultraviolet spectral region. Such light sources are employed for a variety of applications within imaging, attosecond spectroscopy, and high-precision frequency metrology. LÄS MER

7. 5. Imaging Living Cells with an X-ray Laser

   Författare :Gijs van der Schot; Tomas Ekeberg; Janos Hajdu; Filipe Maia; Pierre Thibault; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Coherent diffractive X-ray imaging; flash X-ray imaging; lensless imaging; single particle imaging; cyanobacteria; phasing; image classification; substrate-free sample delivery; X-ray free-electron laser; XFEL; FEL; CDXI; CDI; CXI; FXI; Chemistry with specialization in Biophysics; Kemi med inriktning mot biofysik;

   Sammanfattning : Imaging living cells at a resolution higher than the resolution of optical microscopy is a significant challenge. Fluorescence microscopy can achieve a degree of super-resolution via labeling cellular components with a fluorescent dye. LÄS MER