title: Hybrid bilayer plasmonic metasurface efficiently manipulates visible light.
abstract: Metasurfaces operating in the cross-polarization scheme have shown an interesting degree of control over the wavefront of transmitted light. Nevertheless, their inherently low efficiency in visible light raises certain concerns for practical applications. Without sacrificing the ultrathin flat design, we propose a bilayer plasmonic metasurface operating at visible frequencies, obtained by coupling a nanoantenna-based metasurface with its complementary Babinet-inverted copy. By breaking the radiation symmetry because of the finite, yet small, thickness of the proposed structure and benefitting from properly tailored intra- and interlayer couplings, such coupled bilayer metasurface experimentally yields a conversion efficiency of 17%, significantly larger than that of earlier single-layer designs, as well as an extinction ratio larger than 0 dB, meaning that anomalous refraction dominates the transmission response. Our finding shows that metallic metasurface can counterintuitively manipulate the visible light as efficiently as dielectric metasurface (~20% in conversion efficiency in Lin et al.'s study), although the metal's ohmic loss is much higher than dielectrics. Our hybrid bilayer design, still being ultrathin (~λ/6), is found to obey generalized Snell's law even in the presence of strong couplings. It is capable of efficiently manipulating visible light over a broad bandwidth and can be realized with a facile one-step nanofabrication process.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore.
authors.forename: Fei
authors.initials: F
authors.lastname: Qin
authors.affiliation: Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 117602 Singapore, Singapore.
authors.forename: Lu
authors.initials: L
authors.lastname: Ding
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Francesco
authors.initials: F
authors.lastname: Monticone
authors.affiliation: Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 117602 Singapore, Singapore.
authors.forename: Chan Choy
authors.initials: CC
authors.lastname: Chum
authors.affiliation: Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 117602 Singapore, Singapore.
authors.forename: Jie
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore.; Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456 Singapore, Singapore.
authors.forename: Shengtao
authors.identifier: 0000-0002-2133-9228
authors.initials: S
authors.lastname: Mei
authors.affiliation: SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Shenzhen University, Guangdong 518060, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 117602 Singapore, Singapore.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Teng
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore.
authors.forename: Minghui
authors.initials: M
authors.lastname: Hong
authors.affiliation: School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Alù
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore.; SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Shenzhen University, Guangdong 518060, China.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Qiu
mesh_terms: D004867:Equipment Design / Q000379:methods; D008027:Light; D036103:Nanotechnology / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*
keywords: Metasurface; high efficiency; plasmonics; visible light, coupling