Acoustic metasurfaces

Extremely Asymmetrical Acoustic Metasurface Mirror at the Exceptional Point

“…As an example, the metasurface mirror is designed to have high-efficiency retro-reflection when the wave incidents from one side and near-perfect absorption when the wave incidents from the opposite side. This work marries conventional gradient index metasurfaces with the exceptional point from non-Hermitian systems, and paves the way for identifying new mechanisms and functionalities for wave manipulation.Molding the flow of acoustic energy using functional materials is a research area that has recently generated a proliferation of work [1][2][3][4][5][6]. As a member of functional acoustic materials, acoustic metasurfaces stand out as a distinct choice for wave manipulation owing to their advanced capabilities on sound control as well as their vanishing size [6-10].…”

Dispersion tuning and route reconfiguration of acoustic waves in valley topological phononic crystals

“…Despite intensive research on tunable acoustic systems [34][35][36][37][38][39][40][41][42][43][44][45][46][47] , including metamaterials [35][36][37][38][39] , metasurfaces [40][41][42] , recently reported topological insulators 43 , and rotatable-unit-based valley PCs 34 , tuning the dispersion (frequency, wavenumber, and slope) of topological states for acoustic waves is challenging. For previously reported topological acoustic systems, including two of the most recent designs 34,43 , it remains difficult to continuously tune the frequencies of topological states over a wide range, because the frequencies are inherently tied to fixed lattice constants and unit cell designs.…”

Fano‐Like Acoustic Resonance for Subwavelength Directional Sensing: 0–360 Degree Measurement

“…[4][5][6][7] Moreover, for small animals (lizards), subwavelength sensing employs dipolar resonances through the two internally coupled eardrums (membranes) that permit instantaneous pressure difference across the membrane. [8][9][10][11] Despite their promising performance, the bioinspired directional sensors based on such an internal coupling or structurally coupled resonators pose challenges associated with dedicated sensing components and a limited sensing range (i.e., from 0° only up to 180°).Pioneering metamaterial-based devices exhibit superior capability of acoustic wave control [12][13][14][15][16][17][18] and wave sensing. [1,2,[19][20][21][22] Particularly, directional sound reception in a narrow angle range (rejecting noise from the other angles) is enabled by topological insulator with valley polarized edge states [19] and phononic crystals.…”

“…Pioneering metamaterial-based devices exhibit superior capability of acoustic wave control [12][13][14][15][16][17][18] and wave sensing. [1,2,[19][20][21][22] Particularly, directional sound reception in a narrow angle range (rejecting noise from the other angles) is enabled by topological insulator with valley polarized edge states [19] and phononic crystals.…”