An Ultrahigh Numerical Aperture Microwave Metalens With Ultrathin Thickness

IF 4.8 2区计算机科学 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Antennas and Wireless Propagation Letters Pub Date : 2025-06-23 DOI:10.1109/LAWP.2025.3582161

Yong-Qiang Liu;Wei Dai;Jinhai Sun;Yue-Yi Zhang;Chao-Hai Du

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引用次数: 0

Abstract

Ultrahigh numerical aperture (NA) metalenses can produce a tight focusing spot with highest resolution very close to diffraction limit. So far, several ultrahigh metalenses have been presented, but mostly with dielectric metasurfaces for experimentally reported NA < 1 and with bulky device thickness compared to its wavelength λ. In this letter, an ultrahigh NA metalens (spot size is as small as 0.5λ, NA = 1) by using multilayer plasmonic metasurface with only 0.24λ thickness is demonstrated both numerically and experimentally. Notably, this measured NA = 1 is the highest level among all of the reported ultrahigh NA metalenses in the free space. Besides, the measured focusing efficiency can reach a large 31%, which can also be compared to the state-of-the-art ultrahigh NA metalenses. Such an ultrahigh resolution focusing in axial also produces a tight longitudinal depth of focus (DOF) of 2.3λ and 3λ according to simulations and measurements, respectively. The presented metalens can find potential applications such as ultrahigh resolution microwave imaging, compact wireless power harvesting or transfer systems, miniaturized communication or sensing systems, and many others.

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一种超薄厚度的超高数值孔径微波超透镜

超高数值孔径（NA）超透镜可以产生非常接近衍射极限的高分辨率紧密聚焦光斑。到目前为止，已经出现了几种超高超透镜，但大多数是实验报道的NA < 1的介电超表面，并且与波长λ相比，器件厚度较大。本文利用厚度仅为0.24λ的多层等离子体超表面，通过数值和实验证明了一种超高NA超透镜（光斑尺寸小至0.5λ, NA = 1）。值得注意的是，在所有报道的自由空间超高NA超构透镜中，测量到的NA = 1是最高的。此外，测量的聚焦效率可以达到31%，也可以与最先进的超高NA超透镜相媲美。这种超高分辨率轴向聚焦也产生了紧密的纵向焦深（DOF），分别为2.3λ和3λ，根据模拟和测量。所提出的超构透镜可以找到潜在的应用，如超高分辨率微波成像，紧凑型无线能量收集或传输系统，小型化通信或传感系统等。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

IEEE Antennas and Wireless Propagation Letters 工程技术-电信学

CiteScore

8.00

自引率

9.50%

发文量

529

审稿时长

1.0 months

期刊介绍： IEEE Antennas and Wireless Propagation Letters (AWP Letters) is devoted to the rapid electronic publication of short manuscripts in the technical areas of Antennas and Wireless Propagation. These are areas of competence for the IEEE Antennas and Propagation Society (AP-S). AWPL aims to be one of the "fastest" journals among IEEE publications. This means that for papers that are eventually accepted, it is intended that an author may expect his or her paper to appear in IEEE Xplore, on average, around two months after submission.