Plasma dynamics of water breakdown at a water surface induced by femtosecond laser pulses

Femtosecond laser pulse induced ultrafast plasma dynamics studies of water breakdown in the range up to 250 ps are reported. We combine transient imaging techniques together with spectrally resolved reflection spectroscopy to monitor the early breakdown dynamics at the water surface with a laser intensity being 1.5 above threshold. We observe a 20 ps delay before the plasma expands with an initial velocity of 5900 m/s. The transient electron density after formation of the plasma is 1.2x10(21)/cm(3). A recombination on a picosecond time scale with a rate of (1.6x10(-9)+/- 0.3x10(-9)) cm(3)/s is found.