The high-efficiency transmitted acoustic focusing lenses based on the Helmholtz resonator (HR) metasurface is reported. The proposed lenses demonstrate superior focusing performances, which can provide deep-subwavelength resolution. The proposed lenses demonstrate superior focusing performances, in which the performances of acoustic focusing metasurface is investigated in details and the bandwidth of the metasurface with hybrid resonant structures is broadened. For the former, the effects of different numerical apertures, different focusing distances, and different incidence angles are investigated. At the same time, off-axis focusing and spherical wave focusing lenses are also demonstrated. For the latter, by spacing the HR elements with different resonant frequencies, a broad-band acoustic lens is also designed and achieved, in which the favorable focusing performance can be realized in a relative wider frequency range. The proposed designs provide great potential applications in many scenarios, such as nondestructive testing, ultrasonic medical treatment and so on.

中文翻译：

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基于亥姆霍兹谐振器超表面的高效声学聚焦透镜

报道了基于亥姆霍兹谐振器 (HR) 超表面的高效透射声学聚焦透镜。所提出的镜头表现出卓越的聚焦性能，可以提供深亚波长分辨率。所提出的透镜表现出优异的聚焦性能，其中详细研究了声聚焦超表面的性能，并拓宽了具有混合谐振结构的超表面的带宽。对于前者，研究了不同数值孔径、不同焦距和不同入射角的影响。同时，还展示了离轴聚焦和球面波聚焦透镜。对于后者，通过间隔不同谐振频率的 HR 元件，还设计并实现了宽带声学透镜，其中可以在相对较宽的频率范围内实现良好的聚焦性能。所提出的设计在许多场景中提供了巨大的潜在应用，例如无损检测、超声医疗等。