Sökning: "Laser excitation"

Visar resultat 11 - 15 av 117 avhandlingar innehållade orden Laser excitation.

  1. 11. Infrared Laser-Induced Grating Techniques for Diagnostics in Reactive Flows

    Författare :Dina Hot; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Laser diagnostics; infrared; laser-induced grating spectroscopy; degenerate four-wave mixing; flames; temperature; concentration; Fysicumarkivet A:2020:Hot;

    Sammanfattning : AbstractThe work presented in this thesis is mainly focused on the development andapplication of infrared laser-induced grating techniques in order to measure the gasphase temperature and species concentrations in reactive flows. The two techniquesused for this purpose are laser-induced grating spectroscopy (LIGS) and degeneratefour-wave mixing (DFWM). LÄS MER

  3. 12. Development and application of photofragmentation laser-induced fluorescence for visualization of hydrogen peroxides

    Författare :Olof Johansson; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Flame diagnostics; Fluorescence lifetime imaging; Hydrogen peroxide; Laser diagnostics; Laser-induced fluorescence; Photofragmentation;

    Sammanfattning : The work presented in this thesis is mainly motivated by the need for an optical diagnostic technique which can be used to visualize hydrogen peroxide (H2O2) in its gas phase. Due to the lack of bound electronic states, H2O2 cannot be detected using laser-induced fluorescence based on electronic excitation. LÄS MER

  4. 13. Ionization of large molecules with short laser pulses

    Författare :Mikael Kjellberg; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik; Photoelectron spectroscopy; Momentum mapping imaging; thermal ionization; above threshold ionization; molecular fusion; fullerenes; polyaromatic hydrocarbons; femtosecond-laser.;

    Sammanfattning : The decay dynamics of fullerenes and polyaromatic hydrocarbons (PAH) after femtosecond-laser excitation have been studied experimentally by electron momentum mapping and mass spectrometry. The electron spectra of fullerenes and large PAH-molecules were found to be exponentially decreasing with energy without any distinct peaks outside the photon energy. LÄS MER

  5. 14. Diode laser spectroscopy in extended wavelength ranges

    Författare :Ulf Gustafsson; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diode-laser spectroscopy; frequency-modulation spectroscopy; frequency conversion; fluorescence spectroscopy; scattering; diffraction; Fysicumarkivet A:2000:Gustafsson; Atomic and molecular physics; Atom- och molekylärfysik; absorption spectroscopy;

    Sammanfattning : Diode laser spectroscopy performed in the ultraviolet, visible and infrared spectral regions is presented. The accessible wavelength range for visible and near-infrared diode lasers is extended by the use of sum- and difference-frequency generation. LÄS MER

  7. 15. Time resolved molecular laser spectroscopy

    Författare :Peter Weijnitz; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : A number of experimental and theoretical schemes have been employed to perform time resolved investigations on diatomic molecules. Laser excitation of the molecule in question is the common ground in the cases discussed. LÄS MER