Nanoparticles formed in short pulsed laser materials interaction have strong effects on laser micro-machining, material surface processing, and thin film deposition. In this work, Molecular Dynamics (MD) simulations are conducted to attain physical origins and the nature of nanoparticle formation in picosecond laser materials interaction. The MD simulation reveals that nanoparticles originate from an intense vapor phase explosion process occurring after laser heating. This phase explosion is driven by an accumulated high pressure of the order of 30 MPa in the near surface region. It is observed that nanoparticles start coming out after laser heating as a result of the after-heating intense phase explosion. Also observed is that the pressure in nanoparticles undergoes a reduction because of the temperature decrease and atom re-construction in space. In addition, saturation of the nanoparticle yield is observed when the laser fluence reaches a certain level, which is a result of limited heat penetration depth during laser heating.

This content is only available via PDF.
You do not currently have access to this content.