An active metasurface for real-time multifunctional elastic wave control (Conference Presentation)

We design and experimentally demonstrate a linear active elastic metasurface for real-time and simultaneously multifunctional wave control on a steel plate. The metasurface consists of an array of circuit-controlled piezoelectric patches bonded on the plate separated by thin slots for active wave phase modulations. Our experiments illustrate that by properly programming digital circuits of metasurface unit cells, wave steering directions and paths can be arbitrarily tuned in real-time, which also has an excellent agreement with numerical simulations. We further explore that multiple wave control functions can be integrated into one within the circuits to achieve a simultaneously multifunctional wave control device by using only one metasurface layer. Our numerical results prove the feasibility of the design for broadband and oblique incident applications. The active metasurface breaks the time-revisal symmetry and behaves nonreciprocal propagations of elastic waves. Our design can be simply extended for other elastic wave mode control and wave mode conversion. We believe that the proposed active elastic metasurface could open new avenues for novel and unconventional real-time elastic wave control applications.