Phase explosion in atmospheric pressure infrared laser ablation from water-rich targets

A fluid dynamics model was developed for the ablation of water-rich targets by infrared laser pulses at atmospheric pressure. It incorporates the nonlinear absorption of water and the phase explosion due to superheating. The simulation results show that due to two different phase transition mechanisms, the first, slower plume expansion is followed by a vigorous accelerated expansion. The calculated time evolution of the shock front agrees well with the experimental observations. This model sheds new light on the effect of phase explosion on laser ablation dynamics, and it is relevant for the preparative, analytical, and medical applications. (c) 2006 American Institute of Physics.