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Visar resultat 16 - 20 av 89 avhandlingar som matchar ovanstående sökkriterier.

1. 16. 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

3. 17. Techniques and Application of Electron Spectroscopy Based on Novel X-ray Sources

   Författare :Stefan Plogmaker; Hans Siegbahn; Håkan Rensmo; Emma Springate; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; High Harmonic Generation HHG; HELIOS; X-ray Beam Chopper; Dye-sensitized Solar Cell; Ultra High Vacuum UHV; Photoelectron Spectroscopy; Pump-Probe; XUV; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   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. 18. Millimeter and Sub-Millimeter Wave Integrated Active Frequency Down-Converters

   Författare :Yu Yan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 145 GHz; self-oscillating mixer; mixer; conversion gain; millimeter wave; radar; mHEMT; noise figure; monolithic; sub-millimeter wave; InP; THz; resistive mixer; Gilbert mixer; DHBT; SiGe; 340 GHz; 220 GHz; FMCW; transconductance mixer; BiCMOS; transceiver; harmonic; GaAs;

   Sammanfattning : In recent years, the increasing amount of data transmission, the need for automotiveradars, and standoff imaging for security applications are the main factors that accelerateresearch in the millimeter and sub-millimeter wave frequency ranges. The semiconductorindustries have continuously developed their processes, which have opened upopportunities for manufacturing monolithically integrated circuits up to a few hundredGHz, based on transistor technologies. LÄS MER

5. 19. Angle-resolved photoemission study of unconventional cuprate superconductors

   Författare :Qinda Guo; Oscar Tjernberg; Andrea Damascelli; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Unconventional superconductivity; cuprate; high harmonic generation; narrow bandwidth light source; spherical grating based monochromator; time- and angle-resolved photoemission spectroscopy; Okonventionell supraledning; kuprat; hög övertonsgenerering; ljuskälla med smal bandbredd; sfäriskt gitterbaserad monokromator; tids- och vinkelupplöst fotoemissionsspektroskopi;

   Sammanfattning : Understanding unconventional superconductivity remains one of the most important unsolved problems in physics. A particularly noteworthy case is the copper-based high-temperature superconductor, which stands out due to its remarkably high transition temperature and relatively simple structure. LÄS MER

7. 20. Modelling of laser plasma interaction with applications to particle acceleration and radiation generation

   Författare :Benjamin Svedung Wettervik; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; plasma; ion acceleration; continuum methods; electron wakefield acceleration; raditation generation; coherent X-ray pulses; Vlasov-Maxwell equations;

   Sammanfattning : The development of laser systems with ultra-high intensities has allowed the study of the relativistic interaction of laser light and ionized matter, plasmas, as well as opened up prospects for compact particle accelerators, generation of high intensity X-ray, XUV radiation, and probing QED-effects, which are present in the high intensity regime. To describe laser matter interaction, it is necessary to self-consistently account for the paths of a large number of particles and the corresponding electromagnetic fields, with the addition of stochastic effects at high laser intensities. LÄS MER