Sound‐Speed Modifying Acoustic Metasurfaces for Acoustic Holography

Acoustic metasurfaces offer unique capabilities to steer and direct acoustic fields, though these are generally composed of complex 3D structures, complicating their fabrication and applicability to higher frequencies. Here, an ultrathin metasurface approach is demonstrated, wherein planarized micropillars in a discretized phase array are utilized. This subwavelength metasurface is easily produced via a single‐step etching process and is suitable for megahertz‐scale applications. The flexibility of this approach is further demonstrated in the production of complex acoustic patterns via acoustic holography. This metasurface approach, with models used to predict their behavior, has broad potential in applications where robust, high‐frequency acoustic manipulation is required, including microfluidics, cell/tissue engineering, and medical ultrasound. An ultrathin metasurface approach utilizing planarized micropillars in discrete phase arrays is demonstrated, and which is easily fabricated by a single‐step etching process. This metasurface demonstrates flexibility in the generation of complex acoustic patterns by acoustic holography and has broad potential in applications including high‐frequency acoustic manipulation in microfluidics, cell/tissue engineering, and medical ultrasound.