Observation of resonant states in negative refractive photonic crystals

In this paper, experimental evidences about the resonance phenomena in a negative 2D photonic crystal are shown. Localized plasmon-like modes and guided mode resonances are detected in the reflectivity spectrum of a photonic crystal slab irradiated with out-of-plane incident radiation. The strong confinement of the radiation, in addition to the field enhancement, make photonic crystals a very appealing alternative to plasmonic substrates, avoiding the limits of absorption losses in metals.