Sökning: "laser dynamics"

Visar resultat 1 - 5 av 266 avhandlingar innehållade orden laser dynamics.

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. Approaches to particle acceleration in intense laser-matter interaction

   Författare :Joel Magnusson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; particle-in-cell; nonlinear dynamics; laser; plasma; laser-matter interaction; particle acceleration;

   Sammanfattning : In the interaction of ultra-intense laser fields with matter, the target is rapidly ionized and a plasma is formed. The ability of a plasma to sustain acceleration gradients, orders of magnitude larger than achievable with conventional accelerators, has led to a great interest in laser-driven plasma-based particle acceleration and radiation generation, with applications in materials science, biology and medicine. LÄS MER

4. 3. Development and Application of Single-Ended Picosecond Laser Diagnostics

   Författare :Billy Kaldvee; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Raman Scattering; Temporal Filtering; Picosecond Laser Diagnostics; Rayleigh Scattering; Laser-spectroscopy; DIAL; Laser Combustion Diagnostics; Lidar; Laser-induced Fluorescence; Laser-induced Incandescence; Fysicumarkivet A:2012:Kaldvee;

   Sammanfattning : Light detection and ranging (lidar), a method for nonintrusive, single-ended, and range resolved measurements, has been developed and applied for combustion related diagnostics. Employing picosecond laser pulse durations and detectors providing temporal resolution on the order of picoseconds, lidar has been applied successfully for both quantitative temperature- and species concentration measurements, obtaining an ultimate range resolution of 0. LÄS MER

5. 4. Conduction laser welding : modelling of melt pool with free surface deformation

   Författare :Josefine Svenungsson; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Conduction laser welding; numerical modelling; Computational Fluid Dynamics; OpenFOAM; free surface deformation; melt pool; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik;

   Sammanfattning : Laser welding is commonly used in the automotive-, steel- and aerospace industry. It is a highly non-linear and coupled process where the weld geometry is strongly affected by the flow pattern in the melt pool. Experimental observations are challenging since the melt pool and melt flow below the surface are not yet accessible during welding. LÄS MER

7. 5. Modal Dynamics of Vertical-Cavity Surface-Emitting Lasers

   Författare :Johan Gustavsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; transverse modes; noise; modeling; Semiconductor laser; dynamics; vertical-cavity surface-emitting laser;

   Sammanfattning : In this work, a comprehensive dynamic model has been developed for simulating a novel semiconductor laser type, referred to as the Vertical-Cavity Surface-Emitting Laser (VCSEL). The high-speed behavior was simulated and compared to experiments, where excellent agreement was found. LÄS MER