Probing the formation of femtosecond laser-induced periodic surface structures on silica films by ultrafast small-angle X-ray scattering

Using ultrafast small-angle X-ray scattering (SAXS), we probe the formation of nanoscatterers and nanocracks in reciprocal space as they evolve into different types of laser-induced periodic surface structures (LIPSS) on silica films.

Our focus is on the dynamics and evolution of nanoscatterers and high spatial frequency LIPSS (HSFL), with spatial periods below 100 nm. Our experiments include an in-situ analysis of the pulse-by-pulse evolution of HSFL at a fixed sample location, as well as fs time-resolved delay and fluence scans using an ultrafast pump-probe scheme. We find that nanoscatterers and periodic nanocracks form at delay times of hundreds of picoseconds and subsequently evolve into HSFL.