Multifunctional acoustic logic gates by valley sonic crystals

The emergence of acoustic logic devices has attracted increasing attention owing to its great potential in logical operations and integrated acoustics. In recent years, various types of acoustic logic gates have successively been demonstrated based on artificial materials. However, simultaneous realization of acoustic logic devices with the characteristics of broad bandwidth and high robustness still poses a great challenge. To overcome this, we numerically design and experimentally demonstrate a multifunctional logic gate based on valley sonic crystals (VSCs). In a designed waveguide composed of two VSCs, a pair of valley edge states can be obtained in the domain wall. Additionally, we experimentally design a multifunctional logic gate composed of four VSCs. The logic functions OR and XOR with the fractional bandwidths of 0.24 and 0.19 can be realized at two output ports, which arises from both valley conservation and linear interference mechanisms. More importantly, we experimentally demonstrate the robustness of the logic gate by introducing a V-shaped defect, and the corresponding logic functions and their bandwidths created by the valley transport of edge states are almost immune to backscattering from the V-shaped defect. Compared with the previous acoustic logic gates, the proposed logic gate has the advantages of multifunctionality, broad bandwidth, and high robustness, which may have practical applications in advanced acoustic devices for computing and information processing.