  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.
