Fano Resonances in a Photonic Crystal Covered with a Perforated Gold Film and its Application to Biosensing

Optical properties of the photonic crystal covered with a perforated metal film were investigated and the existence of the Fano-type resonances was shown. The Fano resonances originate from the interaction between the optical Tamm state and the waveguide modes of the photonic crystal. It manifests itself as a narrow dip in a broad peak in the transmission spectrum related to the optical Tamm state. The design of a sensor based on this Fano resonance that is sensitive to the change of the environment refractive index is suggested.