Performing broadband and tunable mathematical operations based on acoustic reconfigurable metasurfaces

Abstract Acoustic metasurfaces can manipulate acoustic waves at subwavelength scales, thus proved to have advantages in constructing novel compact analog computing (CAC) systems. Here, we design an acoustic CAC system based on a nondispersive focusing metasurface (FM) and a reconfigurable reflective metasurface (RRM), which can perform broadband and tunable mathematical operations. The nondispersive FM consists of the sandwich-like-structured units, featuring the non-dispersive effective refractive indexes and high transmission efficiency. The RRM is formed by the amplitude modulator (AM) and π /2-phase modulator ( π /2-PM), where the moving regions in the AM and π /2-PM can control the reflection amplitude and phase distribution of RRM, respectively. The numerical results show that the proposed CAC system can perform spatial differentiation and integration on the incident acoustic wave in the frequency range from 3.0 kHz to 3.9 kHz. This work promises the broadband and tunability that are critical for practical computing devices, paving the way towards acoustic computing applications, wave processing and manipulations.