Robust Purcell Effect of CsPbI_{3} Quantum Dots Using Nonlocal Plasmonic Metasurfaces.

Optoelectronic metadevices control and enhance light-matter interactions by modulating the local optical field that interacts with emitters. However, the optical property of the highly localized mode in the plasmonic metasurface is sensitive to local disorders arising from experimental fluctuations. Recently, the nonlocal mode of metasurfaces has been attracting growing interest because the coupling within the array of plasmonics results in long-range ordering and collective resonances. Here we demonstrate the topological edge states and the nonlocal modes of Au bow ties in a photonic crystal (PHC) lattice. The strong coupling between plasmonic modes and PHC bands opens the topological band gap at the edge of the Brillouin zone and forms the nonlocal mode having a resonant energy insensitive to fluctuations in Au length, resulting in a robust Purcell effect for quantum dots (QDs) coupling with the nonlocal mode in metadevices. The topological band gap and robust enhancement indicate great potential for the nonlocal plasmonic metasurface in quantum photonic devices with novel functionalities.