Airy-Beam-Enabled Binary Acoustic Metasurfaces for Underwater Ultrasound-Beam Manipulation
Airy-Beam-Enabled Binary Acoustic Metasurfaces for Underwater Ultrasound-Beam Manipulation
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DOI：
10.1103/physrevapplied.18.024070
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发表时间：
2022-08-26
影响因子：
4.6
通讯作者：
Chen, Hong
中科院分区：
文献类型：
--
作者：
Hu, Zhongtao;Yang, Yaoheng;Chen, Hong
艾里光束是一种具有无衍射、自加速和自修复特性的特殊光束，它为超声束的操纵提供了巨大的机会。然而，限制Airy波束在超声中广泛应用的一个关键障碍是缺乏简单构建的设备来在水中产生Airy波束。这项工作提出了一个家庭的艾里波束启用二元声学超颖表面（AB BAM），以产生艾里波束水下超声束操纵。AB BAM通过三维（3D）打印设计和制造，具有两个编码位：聚乳酸（这是常用的3D打印材料）单元充当位“1”，水单元充当位“0”。“二元单元在超颖表面上的分布由艾里光束的图案决定。为了展示AB BAM的波前工程能力，设计了几个AB BAM的例子，3D打印，并与平面单元件超声换能器耦合进行实验验证。我们展示了AB BAM的能力，灵活地调整聚焦区域的大小和光束聚焦在3D空间通过改变AB BAM的设计。在不更换ABBAM的情况下，通过调整平面换能器的工作频率，ABBAM的焦深可以连续地和电调谐。叠加方法被利用来使得能够产生复杂的声场，多焦点和字母图案（例如，“W”和“U”）。更复杂的焦点图案被示出为也是通过简单地调整操作频率连续可操纵的。此外，所提出的3D打印AB BAM设计简单，易于制造，生产成本低，具有实现可调焦点尺寸，灵活的3D光束聚焦，任意多点聚焦和连续可操控性的能力，这为超声束操纵创造了前所未有的潜力。
Airy beams are peculiar beams that are nondiffracting, self-accelerating, and self-healing, and they have offered great opportunities for ultrasound-beam manipulation. However, one critical barrier that limits the broad applications of Airy beams in ultrasound is the lack of simply built devices to generate Airy beams in water. This work presents a family of Airy-beam-enabled binary acoustic metasurfaces (AB BAMs) to generate Airy beams for underwater ultrasound-beam manipulation. AB BAMs are designed and fabricated by three-dimensional (3D) printing with two coding bits: a polylactic acid (which is the commonly used 3D printing material) unit acting as a bit "1" and a water unit acting as a bit "0." The distribution of the binary units on the metasurface is determined by the pattern of Airy beam. To showcase the wave-front engineering capability of the AB BAMs, several examples of AB BAMs are designed, 3D printed, and coupled with a planar single-element ultrasound transducer for experimental validation. We demonstrate the capability of AB BAMs in flexibly tuning the focal region size and beam focusing in 3D space by changing the design of the AB BAMs. The focal depth of AB BAMs can be continuous and electronical tuned by adjusting the operating frequency of the planar transducer without replacing the AB BAMs. The superimposing method is leveraged to enable the generation of complex acoustic fields, e.g., multifoci and letter patterns (e.g., "W" and "U"). The more complex focal patterns are shown to be also continuously steerable by simply adjusting the operating frequency. Furthermore, the proposed 3D-printed AB BAMs are simple to design, easy to fabricate, and low cost to produce with the capabilities to achieve tunable focal size, flexible 3D beam focusing, arbitrary multipoint focusing, and continuous steerability, which creates unprecedented potential for ultrasound-beam manipulation.