Versatile on-chip plasmonic lattices enabled by Kekulé metasurfaces

Surface plasmon polaritons (SPPs) lattices created by artificial plasmonic metasurfaces, can carry tremendous optical information and have implications for resilient and secure optical communication. However, tailoring the intensity, spectral, and spatial distributions of these SPP lattices intentionally remain challenging. Here, we develop, theoretically and experimentally, a variety of optical SPP lattices in a category of metasurface named as Kekulé metasurface. This plasmonic nanostructure localizes surface plasmonic polaritons into assorted optical lattices at the two-dimensional limit, visualized by noninvasive leakage radiation microscopy. The spatial distribution and relative intensity of the SPP lattice sites are evolved and tailored by superposing an extra wing-shaped nanoslit set. A configurable on-chip light-emitter array and high-security imaging encryption/decryption using such optical lattices are further demonstrated. This work reports a versatile Kekulé metasurface platform and well-defined SPP lattices with multiple degrees of freedoms, featuring rich physic phenomena and potential photonic elements for applications into existing technologies.