Metafocusing by a Metaspiral Plasmonic Lens.

We designed and realized a metasurface (manipulating the local geometry) spiral (manipulating the global geometry) plasmonic lens, which fundamentally overcomes the multiple efficiency and functionality challenges of conventional in-plane plasmonic lenses. The combination of spirality and metasurface achieves much more efficient and uniform linear-polarization-independent plasmonic focusing. As for functionality, under matched circularly polarized illumination the lens directs all of the power coupled to surface plasmon polaritons (SPPs) into the focal spot, while the orthogonal polarization excites only diverging SPPs that do not penetrate the interior of the lens, achieving 2 orders of magnitude intensity contrast throughout the entire area of the lens. This optimal functional focusing is clearly demonstrated by near-field optical microscopy measurements that are in excellent agreement with simulations and are supported by a detailed theoretical interpretation of the underlying mechanisms. Our results advance the field of plasmonics toward functional detection and the employment of SPPs in smart pixels, near-field microscopy, lithography, and particle manipulation.

[1]  R. W. Christy,et al.  Optical Constants of the Noble Metals , 1972 .

[2]  Y. Takakura,et al.  Optical resonance in a narrow slit in a thick metallic screen. , 2001, Physical review letters.

[3]  W. Barnes,et al.  Surface plasmon subwavelength optics , 2003, Nature.

[4]  Zhaowei Liu,et al.  Focusing surface plasmons with a plasmonic lens. , 2005, Nano letters.

[5]  Yuan Wang,et al.  Resonant and non-resonant generation and focusing of surface plasmons with circular gratings. , 2006, Optics express.

[6]  Rainer Hillenbrand,et al.  Pseudoheterodyne detection for background-free near-field spectroscopy , 2006 .

[7]  P Lalanne,et al.  Approximate model for surface-plasmon generation at slit apertures. , 2006, Journal of the Optical Society of America. A, Optics, image science, and vision.

[8]  S. Maier.  Plasmonics: Fundamentals and Applications , 2007 .

[9]  E Hasman,et al.  Observation of the spin-based plasmonic effect in nanoscale structures. , 2008, Physical review letters.

[10]  Uriel Levy,et al.  Demonstration of nanofocusing by the use of plasmonic lens illuminated with radially polarized light. , 2009, Nano letters.

[11]  Weibin Chen,et al.  Miniature circular polarization analyzer with spiral plasmonic lens. , 2009, Optics letters.

[12]  Qiwen Zhan,et al.  Plasmonic lens made of multiple concentric metallic rings under radially polarized illumination. , 2009, Nano letters.

[13]  D. Bogy,et al.  Maskless Plasmonic Lithography at 22 nm Resolution , 2011, Scientific reports.

[14]  P. Nordlander,et al.  Plasmonic focusing in symmetry broken nanocorrals. , 2011, Nano letters.

[15]  Erez Hasman,et al.  Optical spin Hall effects in plasmonic chains. , 2011, Nano letters.

[16]  K. A. Bachman,et al.  Spiral plasmonic nanoantennas as circular polarization transmission filters. , 2012, Optics express.

[17]  F. Capasso,et al.  Polarization-Controlled Tunable Directional Coupling of Surface Plasmon Polaritons , 2013, Science.

[18]  Xing Zhu,et al.  Plasmonic focusing in spiral nanostructures under linearly polarized illumination. , 2014, Optics express.

[19]  G. Bartal,et al.  Sub-100 nm focusing of short wavelength plasmons in homogeneous 2D space. , 2014, Nano letters.

[20]  P. Genevet,et al.  Holographic optical metasurfaces: a review of current progress , 2015, Reports on progress in physics. Physical Society.