Dynamic and High-Precision Sound Manipulation by Acoustic Metamaterial-Empowered Phased Arrays

Abstract

High-precision dynamic sound manipulation remains a fundamental challenge in acoustics, crucial for diverse applications. Phased arrays (PAs), widely applied for real-time sound control, are limited in resolution and complexity. Recently-emerged acoustic metamaterials (AMs) significantly simplify high-precision wavefront engineering, yet remain passive with fixed functionalities or have complicated active control systems to enhance resolution. To break through the above limitations, here a metamaterial-empowered PA (MPA) that achieves dynamic sound manipulation with a diffraction limit-approaching resolution using only wavelength-scale transducers is proposed and experimentally demonstrated. It is analytically proven that acoustically shrinking each element by designed AMs substantially eliminates the aliasing effects and enhances the spatial precision of sound manipulation. Thanks to the uniformity of metamaterial units attached one-by-one to PA elements, the produced sound field can be reformed in real time without structural modifications. The unique performance of the MPA is showcased via two typical examples of high-quality programmable focusing and real-time imaging with subwavelength resolution, which is beyond attainable relying solely on current PAs or AMs. The proposed mechanism offers an integrated and low-cost solution to the long-standing challenge of dynamic and high-precision wave manipulation and has far-reaching impacts from biomedical imaging to nondestructive evaluation.