Spatially varying near-resonant aperture arrays for beam manipulation

Enhanced transmission has been associated with surface wave excitation and aperture arrangement on a metallic film. Aperture resonances, however, have been demonstrated to exist without an order in the arrangement of apertures, with properties dependent on geometry and optical properties of the aperture filling. These resonances are accompanied by wavelength-dependent phase shifts in the transmitted fields offering the potential for manipulation of wavefields. Here, we present Finite Element Method simulations investigating light passing through periodic arrays of nanometric spatially varying near-resonant slits perforated in a metallic film. We show that a tailored phase modulation can be introduced into an incident optical wavefield by varying aperture sizes around the resonant dimensions for a particular design wavelength, permitting control of wavefields which can be employed for beam deflection, beam focusing or for producing a wavelength-specific spatial field change.