Nanostructuring Process in Femtosecond Laser Ablation of Patterned Thin Film Surfaces

Abstract

To study the physical mechanism of femtosecond (fs) laser induced nanostructuring on solid surfaces, we observed the initial stage of morphological change on diamond-like carbon and titanium nitride films in fs laser ablation at low fluence. Using the thin film targets patterned with submicrometer-size stripes, we have found that the nanostructure starts to be formed on the stripe along the direction perpendicular to the laser polarization. The experimental results have shown that nanoscale ablation for the nanostructuring is preferentially initiated with the enhancement of localized electric field on the stripe surface with high curvature.