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All‐Dielectric Kissing‐Dimer Metagratings for Asymmetric High Diffraction
Author(s) -
Shi Tan,
Wang Yujie,
Deng ZiLan,
Ye Xuan,
Dai Zhenxing,
Cao Yaoyu,
Guan BaiOu,
Xiao Shumin,
Li Xiangping
Publication year - 2019
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201901389
Subject(s) - diffraction , materials science , optics , scattering , bandwidth (computing) , broadband , wavefront , computer science , physics , telecommunications
Transcending the common perceptions of phase‐gradient metasurfaces, metagratings emerge as a new paradigm for wavefront manipulation directly on the desired diffraction order with ultrahigh deflection angles. However, previous metagratings rely on directional scattering caused by multiresonant interference between multiple separate inclusions, of which the high diffraction efficiencies are only optimized with limited bandwidth and incident angle tolerance. Here, a kind of asymmetric kissing‐dimer metagratings that can achieve broadband high diffraction efficiencies at nearly all incident angles are proposed and experimentally realized. The building block is formed by touching two titanium dioxide polygon pillars with different geometries, which empowers highly directional scattering patterns in nearly the entire visible range. Such kissing‐dimer metagratings possess maximum diffraction up to 90% and flat‐top bandwidth of about 250 nm. This study provides a transformative scheme for ultrahigh performance beam steering devices underpinning various intriguing applications in imaging, sensing, and communication.