Student Fabrication of 3D LIPSS Structure on 304 Stainless Steel Using a Liquid LensWednesday (24.06.2020) 09:00 - 09:20 Room 2
In the past decades, LIPSS (laser-induced periodic surface structures) have been widely investigated and applied in many industry fields [1, 2]. However, many researchers have only focused on 2D plane processing, and the 2.5D (bevel) and 3D (curved surface) processes have been rarely discussed. In the past, the laser focus position was controlled by adjusting a concave lens or using an autofocusing system. Nowadays, liquid lenses are gradually being used to conduct the marching process  because they can adjust the focus position quickly. Therefore, a liquid lens was used in this research to control the focusing position and achieve the 2.5D or even 3D curved surface process.
In this study, 304 stainless steel was irradiated by a femtosecond fiber laser (1030 nm) with a liquid lens. The laser light was reflected by several mirrors and passed through a liquid lens before finally focusing on the sample by the scanner, as shown in Figure 1. Figure 2 shows the top-view structure with periods of around 967 nm, which were slightly less than the laser wavelength. The structure orientation was perpendicular to the laser polarization in the 2D process. The result was consistent with that of a previous study. In the 2.5D process, as shown in Figure 3, the structure was continuous from the top side to bottom side. The period of the structure was around 981 nm.