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The optical response of regularly arranged noble metal wires with nanoscopic cross sections (nanowire gratings) strongly depends on the polarization direction of the incident light. We use silver and gold nanowire gratings produced by electron beam lithography to study this effect by optical extinction spectroscopy. For a polarization direction perpendicular to the wire axis, the excitation of a dipolar plasmon mode dominates the extinction spectrum. The spectral position of the plasmon resonance can be tuned by an appropriate choice of nanowire geometry and material. For a polarization direction parallel to the wire axis, the profile of the extinction spectrum varies mainly as a function of the grating constant. In particular, a transmission maximum for small grating constants is found. By combining the surface plasmon excitation and grating effect for orthogonal polarization directions, a spectrally selective polarizer with an extinction ratio of 26 is demonstrated.

Films of identically shaped, elongated, and parallel-oriented metal nanoparticles arranged in a regular pattern upon a transparent substrate were produced by use of electron-beam lithography. Because of the strong difference in the particles' polarizability components, the optical extinction spectra show strong dichroism. Moreover, one can shift the spectral position of the extinction maximum in a wide range from 480 to 600 nm by variation of the particles' aspect ratio. This result suggests that designed metal particle films can be used as artificial optical thin-film media.

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