Quasicrystalline Arrays and Moiré Patterns in Nematic Liquid Crystals for Soft Photonics

Abstract The search for new strategies for large‐scale, self‐assembled arrays of soft objects is key for many applications in photonics and bottom‐up manufacturing. This work shows how liquid crystal topological defects can be assembled in controlled, aperiodic arrays. In particular, the focus is on two typical examples: quasicrystals and moiré patterns. Thanks to a combination of topographical cues, specifically a micropillar array and electrical switching, defects can be assembled in a quasicrystal structure, as seen from polarized optical microscopy and from diffraction patterns. In this setting, the liquid crystal defects assemble in multiple patterns that can be switched by tuning the applied electric field and retain the quasicrystalline symmetry. Using topographic cues, it is also possible to induce moiré patterns of defects, characterized by a long wavelength superimposed on the periodic structures over a short scale. Even when the defect density increases and the short‐scale periodicity is lost, the long‐scale one remains. This work shows how versatile the combination of topographic confinement and electro‐optic effect is, giving access to patterns that are otherwise difficult to realize.