Hybrid polaritonic switch with light-controlled Rabi splitting in molecular plasmonic system

Polaritonic switches and light control of strong coupling in molecular plasmonic systems are of fundamental and technological interest. Here, we show that coupling strength is made tunable in a photoswitchable plasmonic cavity formed at the interface between a metal and a chromophore-containing polymer. This setup is much simpler than approaches based on individual quantum emitters in high finesse optical cavities. We demonstrate reversible photoswitchable in operando Rabi splitting of ∼600 meV, as high as ∼29% of the molecular transition energy, and control of the coupling strength via irradiation time and chromophore concentration. The experimental results are confirmed by transfer matrix simulations with losses inherently included via the experimentally measured dielectric functions.