Laser ablation in liquid: Heating, diffusion, and condensation

Abstract

Laser ablation in liquid (LAL) is important technique, which is used for formation of nanoparticles (NP). The LAL processes cover logarithmically wide range of spatiotemporal scales and are not fully understood. The NP produced by LAL are rather expensive, thus optimization of involved processes is valuable. As the first step to such optimizations more deep understanding is necessary. We employ physical models and computer simulations by thermodynamic, hydrodynamic, and molecular dynamics codes in this direction. Absorbing light metal expanding into transparent solid or liquid dielectrics is considered. We analyze interplay between diffusion, hydrodynamic instability, and decrease of surface tension down to zero value caused by strong heating and compression transferring matter into state of overcritical fluids. The primary NPs appear through condensation during expansion and cooling of diffusion zone or pure gold vapor zone when pressure in these zones drops below critical pressure for a metal.