Plasmon-like surface states in negative refractive index photonic crystals

In this paper, the presence of localized plasmon-like modes at the surface of a silicon two-dimensional photonic crystal slab is demonstrated. In analogy with surface plasmons supported in metals, we observe that, in a photonic crystal metamaterial, the electromagnetic surface waves arise from a negative effective permittivity. The proposed device is dimensioned in order to support surface states in a large spectral window (≃1550–1650 nm). The result opens strategies in light control at the nanoscale, allowing on chip light manipulation in a wide frequency range and avoiding the intrinsic limits of plasmonic structures due to absorption losses in metals.