This research paper delves into the exploration of laser-induced periodic surface structures (LIPSS) on a 100 µm thin stainless steel (SS) sheet. Through the application of laser irradiation with wavelengths spanning from 400 to 2400 nm, we systematically generate ladder-like LIPSS across a substantial area, incorporating LIPSS with both low spatial frequency (LSFL) and high spatial frequency (HSFL) simultaneously. Notably, the embedded LIPSS exhibit a linear relationship in the observed spatial periodicity of LSFL and HSFL with wavelengths up to 2000 nm, after which a decrease in periodicity is observed. By employing cross-sectional electron microscopy, we scrutinize the penetration depth of laser radiation or laser-affected zone, in the LIPSS-formed SS sheets, revealing a parallel trend with LSFL and HSFL spatial periodicity. Specifically, the penetration depth increases with wavelength up to 2000 nm, reaching a peak at approximately 13 µm, and subsequently decreases. This distinctive correlation underscores the role of plasma material reorganizational effects in LIPSS formation at higher wavelengths, presenting a new experimental observation to the existing literature. The findings enhance our comprehension of laser–material interactions and hold potential implications for surface engineering and material science applications.
Chaudhary et al. (Mon,) studied this question.