Sökning: "Ultrafast"

Visar resultat 11 - 15 av 149 avhandlingar innehållade ordet Ultrafast.

1. 11. Studies of Ultrafast Relaxation and Photodissociation Processes in Solution

   Författare :Peter Salén; Peter van der Meulen; Jan Davidsson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ultrafast spectroscopy; liquid phase; Physics; Fysik;

   Sammanfattning : This thesis focuses on femtosecond studies of relaxation and photo-induced dissociation processes in the liquid environment. Measurements are performed using both polarization sensitive and magic angle transient absorption spectroscopy with excitation wavelengths of 387 nm and 258 nm and a white light continuum probe. LÄS MER

3. 12. An X-ray Based Spectroscopic Study of Structure Influencing Electrons : Fragmentation, Ultrafast Charge Dynamics and Surface Composition

   Författare :Geethanjali Gopakumar; Olle Björneholm; Carl Caleman; Isaak Unger; Ruth Signorell; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fragmentation; ICD; ETMD; Ultrafast electron dynamics; Surface propensity;

   Sammanfattning : The structure of biomolecules, such as proteins, is intimately connected to the function of the molecules. These structures are often studied using X-ray diffraction. However, the interaction of the X-ray photons with the molecule can excite or ionize its electrons which in turn can causes changes in the molecular structure. LÄS MER

4. 13. Spatial and temporal aspects of intense attosecond pulses for pump-probe experiments

   Författare :Hampus Wikmark; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ultrafast lasers; ultrafast optics; attosecond pulses; pump-probe experiments; XUV light; XUV focusing; wavefront sensing; XUV optics; X-ray optics; Fysicumarkivet A:2019:Wikmark; ultrasnabba lasrar; attosekundspulser; pump-prob-experiment; XUV-ljus; vågfrontmätningar; XUV-optik; Röntgen-optik;

   Sammanfattning : Nuclear and electronic dynamics in atoms and molecules are the foundation of many physical processes and chemical reactions. Often, these dynamics take place on timescales so much shorter than those commonly encountered that they are called ultrafast. LÄS MER

5. 14. Magnetization dynamics of complex magnetic materials by atomistic spin dynamics simulations

   Författare :Raghuveer Chimata; Biplab Sanyal; Olle Eriksson; Koopmans Bert; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ultrafast remagnetization; ultrafast dynamics; magnetism; multiferroics; amorphous alloys; DFT; spinels magnetostriction; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : In recent years, there has been an intense interest in understanding the microscopic mechanism of laser induced ultrafast magnetization dynamics in picosecond time scales. Magnetization switching on such a time scale has potential to be a significant boost for the data storage industry. LÄS MER

7. 15. Time-Resolved Photoemission Electron Microscopy: Development and Applications

   Författare :Lukas Wittenbecher; NanoLund: Centre for Nanoscience; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; PEEM; time-resolved PEEM; ultrafast optics; pulse shaping; plasmonics; semiconductor nanowires; hot electrons; ultrafast microscopy; charge carrier relaxation;

   Sammanfattning : Time-resolved photoemission electron microscopy (TR-PEEM) belongs to a class of experimental techniquescombining the spatial resolution of electron-based microscopy with the time resolution of ultrafast opticalspectroscopy. This combination provides insight into fundamental processes on the nanometer spatial andfemto/picosecond time scale, such as charge carrier transport in semiconductors or collective excitations ofconduction band electrons at metal surfaces. LÄS MER