Graphene aperture-based metalens for dynamic focusing of terahertz waves
Graphene aperture-based metalens for dynamic focusing of terahertz waves
复制标题
用于太赫兹波动态聚焦的石墨烯孔径超透镜
DOI：
10.1364/oe.26.028038
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发表时间：
2018-10-15
期刊：
影响因子：
3.8
通讯作者：
Fan, Chunzhen
中科院分区：
文献类型：
--
作者：
Ding, Pei;Li, Yan;Fan, Chunzhen
We theoretically study a tunable reflective focusing lens. based on graphene metasurface, which consists of rectangle aperture array. Dynamic control of either the focal intensity or focal length for terahertz circular polarized waves can be achieved by uniformly tuning the graphene Fermi energy. We demonstrate the graphene apertures with the same geometry; however, spatially varying orientations can only control the focal intensity. To change the focal length, the spatially varying aperture lengths are also required. A comparative study between the metalenses, which generate only geometric or both gradient and geometric phase changes, has shown that the apertures' spatially varying length distribution is the key factor for determining the modulation level, rather than the focal length's modulation range. This kind of metalens provides tunable, high-efficiency, broadband, and wide-angle off-axis focusing, thereby offering great application potential in lightweight and integrated terahertz devices. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
