Abstract

The formation of Laser-Induced Periodic Surface Structures (LIPSS) is a universal phenomenon [1] that can be observed in a wide variety of materials under certain irradiation conditions. Although the study of sub-wavelength LIPSS in semiconductors and dielectrics irradiated below bandgap has been particularly intense [2], the formation of LIPSS in metals have also been given attention due to its specific features [3,4,5] that have been related to the characteristics of electron-phonon coupling, plasma density and electron diffusion upon fs-laser irradiation at low repetition rates. In this work we report on the unique characteristics of low spatial frequency LIPSS patterns fabricated in Cr upon high repetition rate fs-laser irradiation employing beam scanning. Highly regular patterns with sub-wavelength period can be produced for a wide range of repetition rates (100’s kHz range), over large areas (~cm²) and high scan speeds (~m/s).

© 2013 IEEE