title: Vertical split-ring resonator based anomalous beam steering with high extinction ratio.
abstract: Metasurfaces created artificially with metal nanostructures that are patterned on surfaces of different media have shown to possess "unusual" abilities to manipulate light. Limited by nanofabrication difficulties, so far most reported works have been based on 2D metal structures. We have recently developed an advanced e-beam process that allowed for the deposition of 3D nanostructures, namely vertical split-ring resonators (VSRRs), which opens up another degree of freedom in the metasurface design. Here we explore the functionality of beam steering with phase modulation by tuning only the vertical dimension of the VSRRs and show that anomalous steering reflection of a wide range of angles can be accomplished with high extinction ratio using the finite-difference-time-domain simulation. We also demonstrate that metasurfaces made of 3D VSRRs can be made with roughly half of the footprint compared to that of 2D nano-rods, enabling high density integration of metal nanostructures.
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Wei-Lun
authors.initials: WL
authors.lastname: Hsu
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Pin Chieh
authors.initials: PC
authors.lastname: Wu
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Jia-Wern
authors.initials: JW
authors.lastname: Chen
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Chen
authors.affiliation: Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Bo Han
authors.initials: BH
authors.lastname: Cheng
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Wei Ting
authors.initials: WT
authors.lastname: Chen
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Yao-Wei
authors.initials: YW
authors.lastname: Huang
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Chun Yen
authors.initials: CY
authors.lastname: Liao
authors.affiliation: Department of Engineering, University of Massachusetts Boston, Boston, Massachusetts 02125, U.S.A.
authors.forename: Greg
authors.initials: G
authors.lastname: Sun
authors.affiliation: 1] Department of Physics, National Taiwan University, Taipei 10617, Taiwan [2] Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Din Ping
authors.initials: DP
authors.lastname: Tsai