Broadband achromatic metalens in terahertz regime
Broadband achromatic metalens in terahertz regime
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太赫兹范围内的宽带消色差超透镜
DOI：
10.1016/j.scib.2019.08.004
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发表时间：
2019-10-30
期刊：
影响因子：
18.9
通讯作者：
Zhuang, Songlin
中科院分区：
文献类型：
--
作者：
Cheng, Qingqing;Ma, Meilin;Zhuang, Songlin
消色差聚焦对于宽带操作是必不可少的，这是最近使用亚表面实现从可见光到红外波长的操作。类似地，可以将多太赫兹功能器件编码为所需的亚表面相位分布。然而，由于每个单位元素的固有色散，金属透镜遭受较大的色差。在这里，我们提出了一种消色差金属透镜，其C形单元元件工作在0.3-0.8太赫兹之间，中心频率带宽约为91%。所设计的金属透镜具有较高的工作效率，峰值时工作效率超过68%，数值孔径较大，达到0.385。我们进一步展示了我们的C型金属透镜的稳健性，考虑了横向形状变形和腐蚀深度的偏差。我们的金属透镜设计为太赫兹超设备在光谱学、飞行时间层析成像和高光谱成像系统中的未来应用开辟了一条道路。(三)2019年科学中国出版社。爱思唯尔出版社、科学中国出版社出版。版权所有。
Achromatic focusing is essential for broadband operation, which has recently been realised from visible to infrared wavelengths using a metasurface. Similarly, multi-terahertz functional devices can be encoded in a desired metasurface phase profile. However, metalenses suffer from larger chromatic aberrations because of the intrinsic dispersion of each unit element. Here, we propose an achromatic metalens with C-shaped unit elements working from 0.3 to 0.8 THz with a bandwidth of approximately 91% over the centre frequency. The designed metalens possesses a high working efficiency of more than 68% at the peak and a relatively high numerical aperture of 0.385. We further demonstrate the robustness of our C-shaped metalens, considering lateral shape deformations and deviations in the etching depth. Our metalens design opens an avenue for future applications of terahertz meta-devices in spectroscopy, time-of-flight tomography and hyperspectral imaging systems. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.