Effect of the Molecular Weight and Density of Ambient Gas on Shock Wave in Laser-Assisted Nanostructuring

This paper presents the results from molecular dynamics simulations that are performed to explore the properties of the shock wave during laser-assisted near field surface nanostructuring. A quasi-three dimensional model is constructed to study systems consisting of over 2 million atoms. This work includes studies on the velocity as well as pressure evolution of shock wave front with respect to different solid/gas molecular mass ratios and different ambient gas densities. The limitation on shock wave formation under the same laser fluence is also investigated. The results show that lower ratio of the solid/gas molecular weight weakens the strength of the shock wave during the nanostructuring process. Additionally, the formation and attenuation of the shock wave under different ambient gas conditions is studied in substantial detail.