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A comparison is presented of a number of simulation techniques that are used to compute the scattering of electromagnetic radiation by metallic nanostructures. The simulation techniques considered here are Mie theory, the T-Matrix null-field method, the discrete-dipole approximation, the finite-element method and the finite-difference time-domain method. The suitability of each technique is compared in terms of the accuracy, computation time and the range of geometries to which it can be applied. Using each technique, we perform example calculations by simulating the optical response of an 80 nm diameter Au sphere in vacuum. Our main conclusions are summarised in tabulated form, so that the findings presented in this article may serve as a useful reference guide to those looking for suitable numerical tools to model the optical response of metallic nanostructures. [ABSTRACT FROM AUTHOR]

We present results of numerical simulations for structures comprised of metallo-dielectric layers in which the metal layers are perforated with non-diffracting arrays of subwavelength holes, structures that are similar to the 'fishnet' structures being studied as electromagnetic metamaterials. We find for visible frequencies that such structures exhibit a stop-band in transmittance across a broad frequency range, which arises through interactions between two distinctly different types of resonant mode. Using numerical (finite element) modelling to characterise the optical response, we identify strong coupling between Fabry-Perot resonant cavity modes within the multilayer structure and localised surface-plasmon resonances associated with the nanoholes. Our simulations show that the spectral position and width of the stop-band that occurs within the visible frequency range can be tuned by varying both the cavity spacing and the geometry of the nanohole array. [ABSTRACT FROM AUTHOR]