Sökning: "HHG"
Visar resultat 1 - 5 av 19 avhandlingar innehållade ordet HHG.
1. Ultrafast Magnetization Dynamics : Element-selective studies of magnetic alloys using ultra short XUV pulses
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
2. Constructing and Commissioning HELIOS – A High Harmonic Generation Source for Pump-Probe Measurements with sub 50 fs Temporal Resolution : The Development of Experimental Equipment for Extreme Ultraviolet Spectroscopy
Sammanfattning : This thesis presents HELIOS, an in-house laboratory for time-resolved pump-probe spectroscopy with extreme-ultraviolet (XUV) probe radiation. A wide span of pump wavelengths can be generated using commercial laser equipment while XUV probe radiation is generated via a high harmonic generation process in a noble gas delivering probe photons with energies between 20 eV and 72 eV. LÄS MER
3. Techniques and Application of Electron Spectroscopy Based on Novel X-ray Sources
Sammanfattning : The curiosity of researchers to find novel characteristics and properties of matter constantly pushes for the development of instrumentation based on X-radiation. I present in this thesis techniques for electron spectroscopy based on developments of X-ray sources both in time structure and energy. LÄS MER
4. Second-generation High-Order Harmonic Sources — From CPA to OPCPA
Sammanfattning : This thesis presents two sources of extreme ultraviolet (XUV) radiation based on high-order harmonic generation (HHG) in gases. The sources were developed for experiments requiring high-flux harmonic beams or HHG pulses at high-repetition rate. These were used experimentally to image nano-scale objects. LÄS MER
5. Towards ultrafast imaging with extreme ultraviolet light sources
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