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  • Optodynamic energy conversion efficiency during laser ablation on metal surfaces measured by shadow photography
    Gregorčič, Peter ...
    In this investigation, we used high-speed sha- dow photography to observe fast optodynamic phenomena such as shock waves and the ablation of flat metal surfaces. These phenomena were induced in air ... by a Q-switched Nd:YAG laser ( k = 1,064 nm) with a pulse duration of 4 ns and an excitation pulse energy between 10 and 55 mJ. For a good spatial resolution of the shadowgraphs, we used short illumination pulses (30 ps) from a frequency-doubled Nd:YAG laser ( k = 532 nm). Using the shadowgraphs of the shock wave expansion into a half-space, we measured the optodynamic energy conversion efficiency, defined as the ratio between the mechanical energy of the shock wave and the excitation pulse energy. This efficiency increases with an increasing excitation pulse energy. We also present the characteristic shadowgraphs of the ablation of a black- painted metal surface, where the macroscopic material particles are clearly visible. They follow the shock wave and eventually overtake it. As a result, the shape of the shock wave, which normally expands concentrically into the half-space, has an altered form. The presented results reveal the phenomenon of the laser ablation of coated metal surfaces.
    Vir: Applied physics. A, Materials science & processing. - ISSN 0947-8396 (Vol. 117, iss. 1, Oct. 2014, str. 353-357)
    Vrsta gradiva - članek, sestavni del
    Leto - 2014
    Jezik - angleški
    COBISS.SI-ID - 13414939
    DOI

vir: Applied physics. A, Materials science & processing. - ISSN 0947-8396 (Vol. 117, iss. 1, Oct. 2014, str. 353-357)

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