Femtosecond LIPSS on indium-tin oxide thin films at IR wavelengths

In our work we focused femtosecond laser pulses in the infrared region onto conducting indium-tin-oxide (ITO) thin films. We observed laser induced periodic surface structures (LIPSS) with increasing periodicity close to lambda/10 scaling. We conducted supporting finite-difference time-domain calculations to investigate the origin of these morphologies. The results suggest that the surface forms are rooted in the field localization in the surface pits leading to a periodically increased absorption of the laser pulse energy that creates the observed periodic structures.