Sökning: "ultrafast electron microscope"

Hittade 5 avhandlingar innehållade orden ultrafast electron microscope.

1. 1. 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

3. 2. Towards ultrafast imaging with extreme ultraviolet light sources

   Författare :Jörg Schwenke; Lunds universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Photo emission electron microscopy; Focusing of X-ray radiation; Digital holography; High-order harmonic generation; Free-electron laser seeding; Secondary electron cascades; Fysicumarkivet A:2012:Schwenke;

   Sammanfattning : This thesis reports experimental studies performed with two advanced coherent XUV sources with ultrashort pulse duration, high-order harmonic generation and seeded-free electron laser. High-order harmonic generation (HHG) is the generation of overtones of a fundamental laser pulse in a medium, e.g. noble gases. LÄS MER

4. 3. Photo-induced Structural Dynamics in Transition Metal Dichalcogenides

   Författare :Shaozheng Ji; Jonas Weissenrieder; James Gardner; Oscar Tjernberg; Fabrizio Carbone; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ultrafast electron microscope; coherent shear phonon; photo-induced phase transition; 1T-TaSe2; Td-WTe2; charge density wave; ultrasnabbt elektronmikroskop; koherent skjuvphonon; fotoinducerad fasövergång; 1T-TaSe2; Td-WTe2; laddningsdensitetsvåg; Material and Nano Physics; Material- och nanofysik;

   Sammanfattning : Ultrafast electron microscope (UEM), a combination of transmission electron microscopy and laser-based pump-probe techniques, facilitates ultrafast imaging, diffraction, and electron-spectroscopy with high spatial resolution. The unique advantages of UEM enable local ultrafast dynamic studies in materials, nano-system, and biology. LÄS MER

5. 4. Time-resolved plasmonics in designed nanostructures

   Författare :Eleonora Lorek; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plasmon; Nanostructure fabrication; High-order harmonic generation; Photoemission electron microscopy; Focused ion beam; Fysicumarkivet A:2016:Lorek;

   Sammanfattning : A metal nanoparticle can be considered as consisting of a base of positive ion cores and a sea of free electrons. When the free electrons are displaced, for example, by an incident electric field, a restoring force acts on the electrons. The electrons may then oscillate back and forth until equilibrium is reached. LÄS MER

7. 5. Non-linear attosecond physics at 100 eV

   Författare :Alexander Muschet; Laszlo Veisz; Piotr Matyba; Per Eng-Johnsson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; extreme ultraviolet XUV ; non-linear XUV – matter interaction; high-harmonic generation; photoionization; attosecond physics; isolated attosecond pulses; attosecond XUV pump – XUV probe spectroscopy; fysik; Physics;

   Sammanfattning : Non-linear interactions between light and matter have nowadays a broad range of applications. They are used for frequency doubling in simple laser pointers as well as for a variety of purposes in complex laser systems like the one presented in this thesis. LÄS MER