Dynamic evolution of liquid plasma induced by femtosecond laser pulse

Laser-induced liquid plasma formation and plasma-induced ablation of thrombus will occur in laser atherectomy. In order to avoid damage to blood vessels and increase the ablation rate, it is necessary to conduct simulations and experiments for the interaction process. A spatial and temporal distribution numerical model of laser-induced liquid plasma formation was constructed, and the ionization process in the range of 600μm before and after beam waist was calculated. The plasma profile showed a crescent shape shifted to the laser incident direction. It was found that compared with water, the higher extinction coefficient of blood restricted the plasma area to the focus and optical axis, and the stronger absorption capacity of plasma made the plasma shift toward the laser incident direction. The simulation results can fit the experimental results in water and blood diluent.