Diffractive optical elements based on plasmonic metamaterials

The dispersive properties of plasmonic metamaterials and the ability to tailor their complex transmission strongly suggest their use in versatile optical elements. Here we introduce the idea of such an application in diffractive elements and describe, as a proof-of-principle, two numerical implementations of computer-generated holograms at visible wavelengths that are based on fishnet metamaterials. These holograms consist of large arrays of metamaterial unit cells which have locally varying geometrical parameters into which the desired far-field optical response is encoded. We describe the entire design process for such holograms, discuss their efficiency and critically assess their limitations. (C) 2011 American Institute of Physics. [doi:10.1063/1.3587622]