Laser-induced periodic surface structure formation resulting from single-pulse ultrafast irradiation of Au microstructures on a Si substrate

Abstract

We have observed laser-induced periodic surface structure (LIPSS) formation with sub-micron periodicities after single-pulse ultrafast irradiation of isolated, 110 nm-tall Au microstructures on Si substrates. Fresnel diffraction patterns are established on both the structure surface and surrounding Si substrate when light is scattered by feature edges, and the resultant intensity distribution is partially responsible for LIPSS formation. LIPSS form for any in-plane, laser polarization orientation with respect to surface feature edges, although the LIPSS amplitude varies with the orientation. This explains the formation of LIPSS patterns having different wavevectors and amplitudes after multi-pulse irradiation of initially smooth surfaces.