Bidirectional asymmetric acoustic focusing with two flat acoustic metasurfaces Project supported by the National Natural Science Foundation of China (Grant Nos. 11704193, 11674175, and 11704192), the “333” Project of Jiangsu Province, China (Grant No. BRA2017451), and the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (Grant No. KYCX18_1185). |
(color online) (a) Arrangement of AM with 80 subunits. (b) Schematics of three-layered acoustic space-coiling (TAS) subunit. (c) Transmitted phase shifts (dashed line for left-hand scale) and amplitudes (solid line for right-hand scale) of TAS subunit as a function of t. |