Tamm phonon-polaritons: Localized states from phonon-light interactions

We present experimental evidence of optical Tamm states at the interface of a one-dimensional photonic crystal made of porous Si and hexagonal SiC. This phenomenon occurs in the mid-infrared within the Reststrahlen band where SiC optically behaves as a metal due to phonons. We name the observed interface states Tamm phonon-polaritons by analogy to Tamm plasmon-polaritons at the interface of a photonic crystal and a metal. The high quality factor of the observed resonance makes polar dielectrics attractive materials to achieve Tamm states in the mid-infrared, which could benefit applications such as selective thermal emission and mid-infrared sensing. Published under license by AIP Publishing.