  Understanding the mechanisms and controlling the possibilities of surface
nanostructuring is of crucial interest from fundamental and practical
perspectives. Here we report a direct experimental observation of laser-induced
periodic surface structures (LIPSS) formed near a predesigned gold step edge
following single-pulse femtosecond laser irradiation. A hybrid
atomistic-continuum model fully supports experimental observations. We identify
two key components of single-pulse LIPSS formation: excitation of surface
plasmon polaritons and material reorganization. Our results lay the foundation
towards simple and efficient single laser pulse micromachining.
