Study of surface plasmon polaritons near the photonic-bandgap edge for interphotonic band switching devices

The photonic energy band structures near the bandgap edges of surface plasmon polariton in dielectric lattice structures on a smooth silver film were studied. At the bandgap edges, sharp changes of the surface plasmon polariton's transmittance arise owing to small changes in the refractive index around the lattice structure, which results in the band transition between the pass band and the stop band. On the analogy of 'the phase transition' between the surface plasmon polariton's conductive phase and the insulation phase, the surface plasmon polariton's phase diagram of the 1D lattice structure at a single frequency (λ ≈ 780 nm) with parameters of the pitch and the refractive index of lattice were investigated. At the boundary, the most sensitive transition was found between the second pass band and the first stop band, with the ∼0.5 lattice filling factor. The surface plasmon polariton's phase state has been determined by far-field observation using an optical microscope.