Aberration-free ultra-thin flat lenses and axicons at telecom   wavelengths based on plasmonic metasurfaces
  The concept of optical phase discontinuities is applied to the design and demonstration of aberration-free planar lenses and axicons, comprising a phased array of ultrathin subwavelength spaced optical antennas. The lenses and axicons consist of radial distributions of V-shaped nanoantennas that generate respectively spherical wavefronts and non-diffracting Bessel beams at telecom wavelengths. Simulations are also presented to show that our aberration-free designs are applicable to high numerical aperture lenses such as flat microscope objectives. 
Francesco Aieta, Patrice Genevet, Mikhail A. Kats, Nanfang Yu, Romain   Blanchard, Zeno Gaburro, and Federico Capasso
physics.optics