Demonstration of spin-momentum locking and broadband light trapping in adiabatic plasmonic grating

摘要

The rapid development of plasmonics and metamaterials enriches the interpretation of various phenomena in light-matter interaction. Very recently, evanescent wave mediated spin-momentum (propagation direction) locking phenomenon is demonstrated by several types of nanophotonic structures, revealing the great potential in applications of planar lightwave circuits, quantum optics, and topological photonics. However, the ultrashort propagation time (～fs) in nanostructures hampers the further enhancement of such weak spin-orbit interactions and the functionality realization in nanophotonic applications. Here, we report a numerical study based on an adiabatic plasmonic grating to solve this problem, resulting in achieving spin-momentum locking and broadband light trapping (ultraslow wave) simultaneously.