Engineering the point spread function of layered metamaterials
  Layered metal-dielectric metamaterials have filtering properties both in the frequency domain and in the spatial frequency domain. Engineering their spatial filtering response is a way of designing structures with specific diffraction properties for such applications as sub-diffraction imaging, supercollimation, or optical signal processing at the nanoscale. In this paper we review the recent progress in this field. We also present a numerical optimization framework for layered metamaterials, based on the use of evolutionary algorithms. A measure of similarity obtained using Hoelder's inequality is adapted to construct the overall criterion function. We analyze the influence of surface roughness on the quality of imaging. 
Anna Pastuszczak, Marcin Stolarek and Rafal Kotynski
physics.optics