Absorption enhancement of molecules in the weak plasmon–exciton coupling regime

We report on the experimental and theoretical investigations of enhancing the optical absorption of organic molecules in the weak plasmon–exciton coupling regime. A metal–organic hybrid structure consisting of dye molecules embedded in the polymer matrix is placed in close vicinity to thin metal films. We have observed a transition from a weak coupling regime to a strong coupling one as the thickness of the metal layer increases. The results indicate that absorption of the self-assembled J-aggregate nanostructures can be increased in the weak plasmon–exciton coupling regime and strongly quenched in the strong coupling regime. A theoretical model based on the transfer-matrix method qualitatively confirms the experimental results obtained from polarization-dependent spectroscopic reflection measurements.