Chiral Assemblies of Laser-Printed Micropillars Directed by Asymmetrical Capillary Force

Artificial microstructures composed of chiral building blocks are of great significance in the fields of optics and mechanics. Here, it is shown that highly ordered chiral structures can be spontaneously assembled by a meniscus-directed capillary force arising in an evaporating liquid. The chirality is facilitated by rationally breaking the intrinsic symmetry in the unit cells through cooperative control of the geometry and spatial topology of the micropillars. The interfacial dynamics of the assembly process are studied to show that the sequential self-organization of the micropillars is influenced by the geometries, stiffness, and spatial arrangements. A diversity of chiral assemblies with controlled handedness is yielded by varying the pillar number, height, cross-section, laser power, and spatial topology. Lastly, the differential reflectance of light carrying opposite orbital angular momentums on the assembled chiral architectures are investigated, showcasing their potential in the field of chiral photonics concerning enantioselective response and exceptional optical functions.