Surface plasmon polariton dispersion relation at organic/dielectric/metal interfaces

The dispersion relation of a hybrid photonic–plasmonic system consisting of a light emitting thin organic para-Hexaphenylene (p-6P) layer separated by a dielectric gap from a plasmonic silver film is investigated using leakage radiation spectroscopy. Experimental studies are complemented by numerical simulations for the same structure but in the complementary, inverted configuration. The numerical simulations use as input ellipsometric measurements providing optical constants of p-6P in a wide spectral range. From a comparison between calculated and measured dispersion curves it is concluded that the molecular excitons in the p-6P film, created in the course of ultraviolet illumination of the sample, are de-excited via excitation of a plasmonic mode of the metal film.