Dynamics of laser-induced cavitation in liquid

This paper presents an analysis of the rate of bubble expansion and an estimate of maximum bubble diameter and bubble lifetime prior to collapse. Such data are needed for the optimization of system parameters for elemental analysis in water by laser-induced breakdown spectroscopy (LIBS). Two techniques were used for this study: pump-probe beam deflection and high-speed photography. Plasma in the water bulk was generated by a focussed laser pulse with energy of 140 mJ and pulse duration of 10 ns, operating at the fundamental Nd:YAG laser wavelength (1064 nm). Reasonable agreement on the value of maximum bubble diameter was obtained between the photographic and probe beam deflection results. Reasonable agreement for the total duration of the oscillating cavitation bubble was also obtained for the two techniques, with a mean value of ∼800 μs. A comparison between empirical results and predictions based on the Rayleigh equation is also presented.