Flexible Manipulation of the Reflected Wavefront Using Acoustic Metasurface with Split Hollow Cuboid

Abstract

This work proposes a method for actively constructing acoustic metasurface (AMS) based on the split hollow cuboid (SHC) structure of local resonance, with the designed AMS flexibly manipulating the direction of reflected acoustic waves at a given frequency range. The AMS was obtained by precisely adjusting any one or two types of structural parameters of the SHC unit, which included the diameter of the split hole, the length, width, height, and shell thickness of the SHC. The simulation results showed that the AMS can flexibly manipulate the direction of the reflected acoustic waves, and the anomalous reflection angle obeys the generalized Snell’s law. Furthermore, among the five structural parameters, the AMS’s response frequency band is widest with the hole diameter and height, followed by the length and width, and narrowest with the shell thickness. It is worth noting that comprehensive manipulation of two parameters not only broadens the response frequency band, but also strengthens the effect of the anomalous reflection at the same response frequency. The subwavelength size of the AMS constructed with such a comprehensive method has the advantages of a small size, wide response band, simple preparation, and flexible modulation, and can be widely used in various fields, such as medical imaging and underwater stealth.

Recent Progress in Resonant Acoustic Metasurfaces

“…Acoustic metasurfaces constructed with Helmholtz resonators (HR) have successively achieved exotic acoustic phenomena, such as anomalous reflections, carpet cloak, focusing lens, acoustic diffusion, etc., by tuning structural parameters such as split-hole diameters, the spatial distance of the units and the volume of the cavities [19,20,[51][52][53][54][55][56][57].…”

Research on local sound field intensity control technique in metasurface based on deep neural networks

“…Pentamode acoustic metasurface can further compensate for the narrow-band limitations of traditional metasurfaces [5,6]. So far, researchers have achieved some sound field modulation works through the use of various structural designs such as Helmholtz resonators, coiled channels, mazes, and cavities [7][8][9][10][11][12][13]. Also, the researchers have utilized combinations of different materials, such as a combination of water and silicone rubber or polyurethane composites, to achieve the goal of reflective sound field modulation [14,15], other researchers use bottom-up inversion optimization algorithms to design metasurfaces [16][17][18][19].…”

Tunable double-layer dual-band metamaterial with negative mass density

“…Acoustic metasurfaces, characterized by small dimensions in one spatial dimension and subwavelength thickness, are passive phase-controlled arrays that employ generalized Snell's law to regulate phase changes. They represent a new class of two-dimensional artificial materials with a 'planar' shape [1,2]. Over the past decade, acoustic metasurfaces, also known as acoustic super-surfaces, have emerged as a leading option for acoustic control, leading to rapid advancements and applications in sub-wavelength imaging [3], bandwidth enhancement [4], filtering [5], phase correction [6], focusing [7,8], and acoustic noise reduction [9,10].…”