Nanoscale optical lattices of arbitrary orders manipulated by plasmonic metasurfaces combining geometrical and dynamic phases

Metasurfaces can be used to manipulate light at the subwavelength scale, and miniaturized photonic devices can be designed to generate subwavelength lattices, which are important for exploring phenomena in novel fields of physics such as topology. Analogous to multi-beam interference, plasmonic metasurfaces composed of nano-slit pairs on truncated spiral segments were designed and fabricated to realize lattice wave fields at a subwavelength resolution. The interference of the analogous beams was controlled by combining the geometric and dynamic phases, and lattices of different morphologies were realized by adjusting the orientation and position of the nano-slits simultaneously. The numerical and measured results showed good agreement, demonstrating the feasibility of the method and its ability to miniaturize lattice patterns. Owing to the compactness and flexible tunability, the nanoscale optical lattices generated using the metasurfaces are expected to find wide applications in integrated and on-chip optical systems.