title: Optical near-field microscopy of light focusing through a photonic crystal flat lens.
abstract: We report here the direct observation by using a scanning near-field microscopy technique of the light focusing through a photonic crystal flat lens designed and fabricated to operate at optical frequencies. The lens is fabricated using a III-V semiconductor slab, and we directly visualize the propagation of the electromagnetic waves by using a scanning near-field optical microscope. We directly evidence spatially, as well as spectrally, the focusing operating regime of the lens. At last, in light of the experimental scanning near-field optical microscope pictures, we discuss the lens ability to focus light at a subwavelength scale.
authors.affiliation: Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Université des Sciences et Technologies de Lille, Cité Scientifique, BP 60069, F-59652 Villeneuve d'Ascq Cedex, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Fabre
authors.forename: Loïc
authors.initials: L
authors.lastname: Lalouat
authors.forename: Benoit
authors.initials: B
authors.lastname: Cluzel
authors.forename: Xavier
authors.initials: X
authors.lastname: Mélique
authors.forename: Didier
authors.initials: D
authors.lastname: Lippens
authors.forename: Frédérique
authors.initials: F
authors.lastname: de Fornel
authors.forename: Olivier
authors.initials: O
authors.lastname: Vanbésien