光学
数值孔径
太赫兹辐射
光圈(计算机存储器)
材料科学
衍射效率
物理
全息术
波长
声学
作者
Mengyu Yang,Xipeng Shen,Ziping Li,Zhongquan Wen,Gang Chen,Zhihai Zhang,Gaofeng Liang,Hua Li,Zhengguo Shang
出处
期刊:Optics Letters
[The Optical Society]
日期:2023-08-31
卷期号:48 (17): 4677-4677
被引量:3
摘要
Metalenses have been widely investigated for their features of high design freedom. For practical applications, it is necessary to maximize the efficiency of the metalens. However, it is a great challenge to realize both a high numerical aperture (NA) and high-efficiency metalens in the community. Here, we introduce a method to design a hybrid metalens with a large numerical aperture and high focusing efficiency at terahertz frequency. The hybrid metalens consists of gradient metasurfaces in the central area and metagrating in the peripheral area to achieve high-efficiency beam focusing. To verify this concept, a hybrid metalens with a numerical aperture of 0.95 was designed at λ = 118.8 μm. The simulation results demonstrate that the focusing efficiency of the hybrid metalens is 65.8%. The experimental results show that the designed metalens is able to increase the focusing efficiency from 22.8% to 41.7%. The full widths at half maxima (FWHMs) of the focused spots of the hybrid metalens in the x direction and y direction are 0.72λ and 0.45λ, respectively. The proposed high-efficiency hybrid metalens has promising application prospects in various applications of a complex optical system.
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