Strong Plasmon–Exciton–Plasmon Multimode Couplings in Three-Layered Ag–J-Aggregates–Ag Nanostructures

Plasmon–exciton–plasmon (PEP) couplings in Ag–J-aggregates–Ag (AJA) nanostructures are investigated using the finite element method. By adjusting the geometry and the incident angle, strong couplings among localized surface plasmon resonances (LSPRs), exciton resonances, and surface plasmon polaritons (SPPs) were achieved in the AJA nanostructure, resulting in three new hybridized plexcimon modes. We carefully analyzed the SPP–exciton–LSPR coupling behaviors in the AJA nanostructure based on classic oscillator models and obtained the weighting efficiencies of original modes in three plexcimon modes. It is further found that the PEP couplings in the AJA nanostructure could be modulated by varying the original LSPR mode.