Broadband plasmonic vortex lattice generator based on a hexagonal metasurface

The plasmonic vortex lattice offers significant potential for optical tweezers, biomolecule screening, and femtosecond vortex electron pulse generation. In this study, we demonstrated a broadband plasmonic vortex lattice generator consisting of a hexagonal metasurface etched onto a gold film. By adjusting the orientation of nanoslits in the generator, we can flexibly control the lattice's periodicity, shape, and topological charge. Based on a near-field interference model, we have confirmed that plasmonic vortex lattice manipulation arises from the combined effects of the spiral phase due to spin-orbit coupling and the Pancharatnam-Berry phase induced by nanoslits. Furthermore, by minimizing spiral phase accumulation, we achieve plasmonic vortex field superposition states. We also investigate how hexagonal metasurfaces can create composite plasmonic vortex lattices. These discoveries advance multiparticle trapping and high-capacity quantum information encryption.