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

We investigated laser-induced periodic surface structures (LIPSS) generated on indium-tin-oxide thin films with femtosecond laser pulses in the infrared region. Using pulses between 1.6 and 2.4 µm central wavelengths, we observed robust LIPSS morphologies with a periodicity close to λ/10. Supporting finite-difference time-domain calculations suggests 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.