Search for dissertations about: "free-electron laser"

Showing result 16 - 20 of 56 swedish dissertations containing the words free-electron laser.

  2. 16. X-ray scattering and spectroscopy of supercooled water and ice

    Author : Jonas A. Sellberg; Anders Nilsson; Lars G. M. Pettersson; Thomas Loerting; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; supercooled water; ice; x-ray scattering; x-ray spectroscopy; free-electron laser; kemisk fysik; Chemical Physics;

    Abstract : This thesis presents experimental studies of water and ice at near-atmospheric pressures using intense x-rays only accessible at synchrotrons and free-electron lasers. In particular, it focuses on the deeply supercooled, metastable state and its implications on ice nucleation. READ MORE

  4. 17. Dynamic local structural symmetries and luminescence properties of the yellow emitting phosphor Ce3+-doped Y3Al5O12

    Author : Yuan-Chih Lin; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; neutron scattering; vibrational spectroscopy; phosphor; light emitting diode; luminescence; thermal quenching; garnet;

    Abstract : This thesis centers on investigations of the local structure and vibrational properties of the oxide garnet Y3Al5O12 (YAG), which when substituted with a few percent of the activator ion Ce3+ to replace Y3+ (Y3−xCexAl5O12, YAG:Ce3+) is one of the most important phosphors for solid state lighting. The study builds on a comprehensive analysis of the nature of the phonons and localized vibrational modes in YAG:Ce3+ and how these depend on the Ce3+ concentration and temperature and how they affect key optical properties, such as the intensity and frequency of the emitted light. READ MORE

  5. 18. Understanding the interactions between vibrational modes and excited state relaxation in garnet structured phosphors

    Author : Yuan-Chih Lin; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; thermal quenching.; luminescence; garnet; vibrational spectroscopy; neutron scattering; phosphor; light emitting diode;

    Abstract : This thesis concerns investigations of the local structural environments and vibrational dynamics of the three garnet type oxide phosphors Ce3+-doped Y3Al5O12 (YAG:Ce3+), Ca3Sc2Si3O12 (CSS:Ce3+), and Sr3Y2Ge3O12 (SYG:Ce3+), which show promising optical properties as luminescent materials used in solid state white lighting technologies. The study focuses on a comprehensive analysis of the nature of the long-range vibrations (phonons) in terms of local atomic and molecular motions of the garnet structure, as well as their dependence on the nature of the garnet chemical composition, Ce3+ concentration and temperature. READ MORE

  6. 19. Imaging Living Cells with an X-ray Laser

    Author : Gijs van der Schot; Tomas Ekeberg; Janos Hajdu; Filipe Maia; Pierre Thibault; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Coherent diffractive X-ray imaging; flash X-ray imaging; lensless imaging; single particle imaging; cyanobacteria; phasing; image classification; substrate-free sample delivery; X-ray free-electron laser; XFEL; FEL; CDXI; CDI; CXI; FXI; Chemistry with specialization in Biophysics; Kemi med inriktning mot biofysik;

    Abstract : Imaging living cells at a resolution higher than the resolution of optical microscopy is a significant challenge. Fluorescence microscopy can achieve a degree of super-resolution via labeling cellular components with a fluorescent dye. READ MORE

  7. 20. Control of Coherent Extreme Ultraviolet Light and Light Sources

    Author : Neven Ibrakovic; Atomfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ultrafast lasers; XUV optics; high-order harmonic generation; quantum path interference; opto-optical modulation; free electron lasers; nitrogen lasing; Fysicumarkivet A:2019:Ibrakovic;

    Abstract : Coherent extreme ultraviolet (XUV) light sources are necessary for the investigation of physical processes in the natural length and time scales of atoms. These experiments require a high degree of control of the coherent XUV light. READ MORE