Utilizing fundamental beam-mode shaping technique for top-hat laser intensities in direct laser interference patterning

In this work, a diffractive fundamental beam-mode shaper (FBS) element is combined with a Direct Laser Interference Patterning (DLIP) optical setup to generate a square-shaped top-hat intensity distribution in the interference volume. The interference patterns produced by a symmetrical 4-beam DLIP setup with Gaussian and Flat-top intensity distributions are measured and characterized. The impact of misalignments in the optical setup on the resulting intensity profile is analyzed and supplemented by theoretical calculations of the distorted interference patterns. Finally, top-hat shaped interference patterns can be introduced and utilized in order to generate surface patterns with improved homogeneity which eventually will lead to an improved performance in applications with functionalized surfaces.