Optical Vortices Generation via a Self‐Assembly Photonic Crystal Slab

Optical vortices (OVs), as common phenomena that widely exist in nature, have attracted interest both in fundamental science and applications. Recently, generating OVs by using polarization vortices in the momentum space is demonstrated. This method eliminates the need for precise optical center alignment, which relies on periodic structures. The micro‐spheres self‐assembly method is known as an inexpensive and straightforward means to fabricate periodic structures. Here, self‐assembly photonic crystal (SA‐PhC) slabs are proposed that can be used to generate OVs. With both simulations and experiments, the OVs generation via SA‐PhC slabs is investigated. The designed SA‐PhC slab is fabricated. The momentum‐space polarization vortex of the SA‐PhC slab is directly observed. The field shape and phase distribution of the generated OVs are measured. The work can broaden the applications of SA‐PhC and the generation methods of OVs.