title: Sub-wavelength focusing meta-lens.
abstract: We show that a planar plasmonic metamaterial with spatially variable meta-atom parameters can focus transmitted light into sub-wavelength hot-spots located beyond the near-field of the metamaterial. By nano-structuring a gold film we created an array of meta-lenses generating foci of 160 nm (0.2λ) in diameter when illuminated by a wavelength of 800 nm. We attribute the occurrence of sub-wavelength hotspots beyond the near field to the phenomenon of superoscillation.
authors.affiliation: Optoelectronics Research Centre & Centre for Photonic Metamaterials, University of Southampton, Southampton, SO17 BJ, UK.
authors.forename: Tapashree
authors.initials: T
authors.lastname: Roy
authors.forename: Edward T F
authors.initials: ET
authors.lastname: Rogers
authors.forename: Nikolay I
authors.initials: NI
authors.lastname: Zheludev
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D007909:Lenses; D008567:Membranes, Artificial; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D008567:Membranes, Artificial; D006046:Gold