title: Antireflection gratings for a photonic-crystal flat lens.
abstract: A dielectric structure with effective permittivity and permeability close to -1 operating for propagative waves at optical wavelengths is proposed. This structure is a two-dimensional photonic crystal with refractive index -1, coated by appropriate antireflection gratings. Numerical simulations involving a flat lens made of this optimized crystal illustrate the improvements that antireflection gratings can bring. In particular, following Veselago's proposition, this lens "can focus at a point the radiation from a point source" with negligible reflection losses. The proposed design takes into account the fabrication requirements and can be used for optical devices integrated in planar waveguides.
authors.affiliation: Institut Fresnel, CNRS, Aix-Marseille Université, Ecole Centrale Marseille, Campus de St Jérôme, 13397 Marseille Cedex 20, France.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Smigaj
authors.forename: Boris
authors.initials: B
authors.lastname: Gralak
authors.forename: Raphaël
authors.initials: R
authors.lastname: Pierre
authors.forename: Gérard
authors.initials: G
authors.lastname: Tayeb