Hybrid optical Tamm states in a planar dielectric microcavity

Using spectroscopic experiments, we show the transition from a single cavity mode into two optical Tamm states upon incorporating a thin metal layer into a planar organic microcavity. The eigenenergies of both modes strongly depend on the thickness of the metal and both adjacent dielectric layers. We show that both resonances cannot have the same wavelength indicating a clear anticrossing behavior. The experimentally observed splitting of the cavity mode into two resonances is confirmed via transfer matrix calculations.