Laser surface texturing using a single diffractive optical element as an alternative for direct laser interference patterning

In this work, we introduce a simple and universal optical setup design for laser surface texturing (LST) that provides functionality superior than direct laser interference patterning (DLIP). The method requires only a single periodic diffractive optical element and a focusing lens while enabling unlimited freedom for spatial shaping and amplitude variations. The concept is based on the special behavior of diffraction gratings when illuminating an area on the grating that is close in size to a single period rather than effectively infinite periods as is usually discussed in fundamental grating studies. Empirical optimization for a specific ratio value of grating period and incident laser beam size was done on a two-dimensional intensity distribution by fitting the one-dimensional intensity profile to a periodical squared cosine function. We investigate the design characteristics and tolerance sensitivity for this work regime and discuss some application ideas including practical example suggestion of optical design, and some tailored patterning capabilities allowed by the method. A detailed comparison was made between DLIP setup and the proposed alternative method for LST.