A novel plasmonic waveguide filter design based on three cascaded slot cavities is proposed. The cascaded nanocavities support a united resonant （UR） mode. Light is trapped in the middle nanocavity at telecom- muaication wavelenEth （1550 rim） when the UR mode exists. This phenomenon leads to the efficient transmittance and high Q factor of the plasmonic filter. The resonant wavelength and Q factor can be easily modulated by the cavity radii and the waveguide width.
Beam manipulation by metallic nanoslit arrays with perpendicular cuts inside the slits was investigated numerically.The simulated results performed by the finite element method(FEM)show that perpendicular cuts with different heights can modulate phase retardation of the transmitted light through the slits.With the proper distribution of cut height,a focused beam is achieved in our metallic nanostructure with four-time amplitude at the focus point and half focal length compared to a slit array without cuts inside.By using asymmetric distribution of height amplitude,a beam deflection around 6°can also be realized in our design.
