Light Beam Scattering from the Metal Surface with a Complex Mono- and Two-Periodic Microstructure Formed with Femtosecond Laser Radiation

Currently, the technology of imparting the necessary reflective properties to a surface is becoming increasingly important. Darkening the surface and matting it helps to diffuse the reflected beam and prevent glare. The surface’s reflective properties are determined by its microstructure. Modern pico- and femtosecond lasers make it possible to obtain surfaces with high precision and create various LIPSS (laser-induced periodic surface structure) types. In this article, we describe the process of formation of a complex two-periodic microstructure on the surface of AISI 321 stainless steel under the influence of radiation from femtosecond lasers and describe the process of scattering of a light beam by the resulting surface. Modeling shows that the presence of an additional transparent coating on a flat surface does not improve its scattering properties and does not eliminate glare. In the event that a complex two-periodic structure is formed on the reflective surface and the coating surface, the nature of the reflection has a clearly defined scattered character, regardless of the angle of incidence of the light beam. This study shows the feasibility and effectiveness of forming a two-periodic structure in order to give it stealth characteristics and reduce visibility.