Manipulating elastic waves in real time with programmable metasurfaces (Conference Presentation)

Abstract

Real-time manipulating elastic waves in solid materials is crucial for several applications ranging from active noise and vibration cancellation to inverse methods aiming to either reveal or dissimulate the presence of foreign bodies. Here, we introduce a programmable elastic metasurface with sensing-and-actuating units following feedback control loops. The active units governed by local transfer functions encoded into a digital controller and offering highly flexible and independent phase and amplitude engineering of both transmitted and reflected waves. Through numerical and experimental demonstrations, the programmable metasurface can be a perfect absorber with flexural waves incident from left to right and a perfect transparent mirror with flexural waves incident from right to left. Various other significant demonstrations include steering transmitted (reflected) waves without reflection (transmission) and simultaneously control in both transmitted and reflected domains. Finally, we unveil the relations of the programmable elastic metasurface with nonreciprocity to an effective Willis medium. The design will pave a new efficient way in the field of manipulating of elastic waves.