Superwavelength, wavelength, and subwavelength laser-induced periodic surface structures on zinc and their energy-dispersive x-ray analysis.

Abstract

In this work, we demonstrated simultaneous generation of three types of laser-induced periodic surface structures (LIPSSs) on a metal surface by processing Zn with a linearly polarized femtosecond laser pulse of 100 fs duration at a wavelength of 800 nm. In the center of the laser-processed region (a line), the period was found to be as high as 1470 nm (superwavelength LIPSS), whereas at the outer region, the LIPSS period was found to be as small as 200 nm (subwavelength LIPSS). In between these two regions, the LIPSSs were found to have period of 800 nm (wavelength LIPSS). In the energy-dispersive x-ray (EDX) study, the Zn:O atomic ratio was found to be 70%∶30% in the LIPSS-containing region. In contrast to this, in the region containing no LIPSS, the Zn:O atomic ratio was found to be 90%:10%. Discussion is given on the significance of the observed LIPSS, in terms of their possible growth mechanism and comparison with previously published results.