Thermodynamic modeling of liquid nanodroplet formation through phase explosion of laser-irradiated metal targets
High power laser irradiation of pure metal targets has wide and relevant
applications such as Pulsed Laser Deposition (PLD) of metal-based
materials. The formation of nanoparticles in the laser ablation of metal
targets (with pulses ranging from nanoseconds to femtoseconds) is a complex
phenomenon, which involves competing ablation mechanisms and in-flight
interactions in the plasma plume expelled from the target.
Our study is focused on the phase explosion of the target's external
layers, which give rise to a mixture of vapor phase and liquid nanodroplets
directly produced within the target. Through a thermodynamic approach and a
Monte Carlo simulation we have been able to evaluate the material
composition immediately following the phase explosion and the size
distribution of the expelled nanodroplets.