title: High-efficiency broadband anomalous reflection by gradient meta-surfaces.
abstract: We combine theory and experiment to demonstrate that a carefully designed gradient meta-surface supports high-efficiency anomalous reflections for near-infrared light following the generalized Snell's law, and the reflected wave becomes a bounded surface wave as the incident angle exceeds a critical value. Compared to previously fabricated gradient meta-surfaces in infrared regime, our samples work in a shorter wavelength regime with a broad bandwidth (750-900 nm), exhibit a much higher conversion efficiency (∼80%) to the anomalous reflection mode at normal incidence, and keep light polarization unchanged after the anomalous reflection. Finite-difference-time-domain (FDTD) simulations are in excellent agreement with experiments. Our findings may lead to many interesting applications, such as antireflection coating, polarization and spectral beam splitters, high-efficiency light absorbers, and surface plasmon couplers.
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Shulin
authors.initials: S
authors.lastname: Sun
authors.forename: Kuang-Yu
authors.initials: KY
authors.lastname: Yang
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Wang
authors.forename: Ta-Ko
authors.initials: TK
authors.lastname: Juan
authors.forename: Wei Ting
authors.initials: WT
authors.lastname: Chen
authors.forename: Chun Yen
authors.initials: CY
authors.lastname: Liao
authors.forename: Qiong
authors.initials: Q
authors.lastname: He
authors.forename: Shiyi
authors.initials: S
authors.lastname: Xiao
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Kung
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Guo
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Din Ping
authors.initials: DP
authors.lastname: Tsai