Strong coupling between a plasmon mode and multiple different exciton states

Strong coupling between plasmons and multiple different exciton states (MESs) enables the creation of multiple hybrid polariton states under ambient conditions. These hybrid states possess unique optical properties different from those of their separate identities, making them ideal candidates for exploiting room-temperature multimode hybridization and multiqubit operation. In this study, we revealed the static spectral response properties of plasmon-MES strong coupling via a fully quantum mechanics approach. These theoretical predictions were experimentally demonstrated in plasmonic nanocavities containing two and three different exciton species. Additionally, the dynamical absorption processes of such strong coupling systems were investigated, and results indicated that the damping of the hybrid polariton states induced by the strong coupling could be markedly modulated by the acoustic oscillations from the plasmonic nanocavities. Our findings contribute a theoretical approach for accurately describing the plasmon-MES interactions and a platform for developing the high-speed active plasmonic devices based on multiqubit strong coupling.