Shock waves and cavitation effects in aqueous media induced by ultrafast laser pulses.

The peak pressure evolution during shock wave propagation after optical breakdown in water with pulse durations between 80 ns and 100 fs was investigated by streak photography. The cavitation bubble size was measured through acoustic detection of the bubble oscillation time. The shock wave peak pressure decreased from ≈ 300 kbar at 6 ns to ≈ 10 kbar at 100 fs. The conversion efficiency of absorbed light energy into bubble energy decreased from > 20% at 6 ns to < 5% at 100 fs. The weaker mechanical action of fs-pulses, together with the much lower break-down threshold makes it possible to produce structural effects in cells and biological tissues on a micrometer and submicrometer level. [ABSTRACT FROM AUTHOR]