Plasmonic effects on strong exciton-photon coupling in metal-insulator-metal microcavities

Metal-insulator-metal (MIM) microcavities consisting of a layer of polyvinyl alcohol doped and undoped with cyanine dye molecules were prepared and their reflection and transmission spectra were measured. In the doped-MIM microcavity, dispersion curves determined from the reflection data clearly showed the anticrossing behavior arising from the strong coupling between excitons in the dye molecules and photonic modes supported by the MIM microcavity. The experimental dispersion curves could be well reproduced by a standard expression of the coupled mode dispersions by appropriately taking into account the plasmonic nature of the transverse magnetic mode supported by the MIM microcavity. A large splitting between the transverse electric and transverse magnetic modes in the upper branch of the coupled modes can also be well explained by the plasmonic effects.