Tunable strong exciton-plasmon-exciton coupling in WS₂-J-aggregates-plasmonic nanocavity

A coupling system is proposed to active control of strong exciton-plasmon-exciton coupling, which consists of a silver nanoprism separated from a monolayer WS₂ by J-aggregates. The scattering spectrum of the hybrid system calculated by the finite-difference time-domain (FDTD) method is well reproduced by the coupled oscillator model theory. The calculation results show that strong couplings among WS₂ excitons, J-aggregate excitons, and localized surface plasmon resonances (LSPRs) are achieved in the hybrid nanostructure, and result in three plexciton branches. We further analyze the exciton-plasmon-exciton coupling behaviors and obtain the weighting efficiencies of the original modes in three plexciton branches. The strong couplings between two different excitons and LSPRs can be active manipulated by tuning the temperature or the concentration of J-aggregates. The proposed systems make up a simple platform for the dynamic control of exciton-plasmon-exciton couplings and have potential applications in optical modulators at the nanoscale.