School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
Author bio:
Professor VM Shalaev, School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA Email: shalaev@purdue.edu
We experimentally demonstrate the focusing of visible light with ultra-thin
planar metasurfaces made of concentrically perforated
30-nm-thick gold films. The perforated nano-voids—Babinet-inverted (complementary) nano-antennas—create discrete phase shifts and form a desired wavefront of cross-polarized
scattered light. The signal-to-noise ratio in our complementary nano-antenna design is at least one order of magnitude higher than in previous metallic nano-antenna designs. We first study our proof-of-concept 'metalens' with extremely strong focusing ability: focusing at a distance of only 2.5 μm is achieved experimentally with a 4-μm-diameter lens for light at a wavelength of 676 nm. We then extend our work with one of these 'metalenses' and achieve a wavelength-controllable focal length. Optical characterization of the lens confirms that switching the incident wavelength from 676 to 476 nm changes the focal length from 7 to 10 µm
which opens up new opportunities for tuning and spatially separating light at different wavelengths within small
micrometer-scale areas. All the proposed designs can be embedded on-chip or at the end of an optical fiber. The designs also all work for two orthogonal
linear polarizations of incident light.
关键词
Keywords
metalensnano-antennasplasmonicswavefront shaping
references
Huang FM, Kao TS, Fedotov VA, Chen Y, Zheludev NI. Nanohole array as a lens.Nano Lett2008;8: 2469–2472..
Rogers ET, Lindberg J, Roy T, Savo S, Chad JEet al. A super-oscillatory lens optical microscope for subwavelength imaging.Nat Mater2012;11: 432–435..
Verslegers L, Catrysse PB, Yu Z, Fan S. Planar metallic nanoscale slit lenses for angle compensation.Appl Phys Lett2009;95: 071112..
Lin L, Goh XM, McGuinness LP, Roberts A. Plasmonic lenses formed by two-dimensional nanometric cross-shaped aperture arrays for Fresnel-region focusing.Nano Lett2010;10: 1936–1940..
Gao H, Hyun JK, Lee MH, Yang JC, Lauhon LJet al. Broadband plasmonic microlenses based on patches of nanoholes.Nano Lett2010;10: 4111–4116..
Ishii S, Kildishev AV, Shalaev VM, Chen KP, Drachev VP. Metal nanoslit lenses with polarization-selective design.Opt Lett2011;36: 451–453..
Yu N, Genevet P, Kats MA, Aieta F, Tetienne JPet al. Light propagation with phase discontinuities: generalized laws of reflection and refraction.Science2011;334: 333–337..
Ni X, Emani NK, Kildishev AV, Boltasseva A, Shalaev VM. Broadband light bending with plasmonic nanoantennas.Science2012;335: 427..
Kats MA, Genevet P, Aoust G, Yu N, Blanchard Ret al. Giant birefringence in optical antenna arrays with widely tailorable optical anisotropy.Proc Natl Acad Sci USA2012;109: 12364–12368..
Sun S, He Q, Xiao S, Xu Q, Li Xet al. Gradient-index meta-surfaces as a bridge linking propagating waves and surface waves.Nat Mater2012;11: 426–431..
Aieta F, Genevet P, Yu N, Kats MA, Gaburro Zet al. Out-of-plane reflection and refraction of light by anisotropic optical antenna metasurfaces with phase discontinuities.Nano Lett2012;12: 1702–1706..
Genevet P, Yu N, Aieta F, Lin J, Kats MAet al. Ultra-thin plasmonic optical vortex plate based on phase discontinuities.Appl Phys Lett2012;100: 013101–013103..
Larouche S, Smith DR. Reconciliation of generalized refraction with diffraction theory.Opt Lett2012;37: 2391–2393..
Huang L, Chen X, Mühlenbernd H, Li G, Bai Bet al. Dispersionless phase discontinuities for controlling light propagation.Nano Lett2012;12: 5750–5755..
Kang M, Feng T, Wang HT, Li J. Wave front engineering from an array of thin aperture antennas.Opt Express2012;20: 15882–15890..
Hu D, Wang X, Feng S, Ye J, Sun Wet al. Ultrathin terahertz planar lenses. arXiv: 1206.7011 [physics. optics], 2012.
Chen X, Huang L, Mühlenbernd H, Li G, Bai Bet al. Dual-polarity plasmonic metalens for visible light.Nat Commun2012;3: 1198..
Aieta F, Genevet P, Kats MA, Yu N, Blanchard Ret al. Aberration-free ultrathin flat lenses and axicons at telecom wavelengths based on plasmonic metasurfaces.Nano Lett2012;12: 4932–4936..
Johnson PB, Christy RW. Optical constants of the Noble metals.Phys Rev B1972;6: 4370–4379..
Verslegers L, Catrysse PB, Yu Z, White JS, Barnard ESet al. Planar lenses based on nanoscale slit arrays in a metallic film.Nano Lett2008;9: 235–238..
Ishii S, Shalaev VM, Kildishev AV. Holey-metal lenses: sieving single modes with proper phases.Nano Lett2012;13: 159–163..
Boltasseva A, Atwater HA. Low-loss plasmonic metamaterials.Science2011;331: 290–291..
Kildishev AV, Boltasseva A, Shalaev VM. Planar Photonics with Metasurfaces.Science2013;339: DOI: 10.1126/science.1232009.