The traditional phase gradient acoustic focusing metasurfaces based on the generalized Snell law (GSL) can manipulate acoustic waves freely. However, their applications are limited largely because of their narrow bandwidth, large volume, and single function. To resolve these problems, a kind of window-shape acoustic focusing metasurface (WSAFM) is proposed, the well performed focusing can be obtained by the flexibly varied longitudinal length of two handles inside the basic structure unit (BSU). The results demonstrate that, within multi-breadth bands (5000 Hz –6500 Hz, 7100 Hz –7600 Hz, 12100 Hz –13600 Hz), the WSAFM can realize the near-zero–sidelobe (NZS) subwavelength focusing, the variation of focus position, and the breakthrough of diffraction limit at multi-frequency. More importantly, when the non-Hermitian parameters (non-Hermitian system) are introduced to the WSAFM, the focus intensity can be enhanced without varying other parameters. The WSAFM proposed in this paper shows promising potentials in biomedical ultrasound imaging and the design of acoustic devices with multi-breadth bands.

基于广义斯涅尔定律（GSL）的传统相位梯度声聚焦超表面可以自由地操纵声波。然而，由于它们的窄带宽，大体积和单一功能，它们的应用受到很大限制。为了解决这些问题，提出了一种窗口形状的声聚焦超表面（WSAFM），通过在基础结构单元（BSU）内部灵活地改变两个手柄的纵向长度可以获得良好的聚焦效果。结果表明，在多波段频段（5000 Hz –6500 Hz，7100 Hz –7600 Hz，12100 Hz –13600 Hz）中，WSAFM可以实现近零旁瓣（NZS）亚波长聚焦，聚焦变化位置，以及多频处衍射极限的突破。更重要的是，当将非赫米特参数（非赫米特系统）引入WSAFM时，无需改变其他参数即可增强聚焦强度。本文提出的WSAFM显示了在生物医学超声成像和具有多波段的声学设备设计方面的潜在潜力。