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) Intensity contrasts |p/p0|2 on dotted line “II” for (a) PD case and (b) ND case at the working frequencies f = 3.232, 3.332, 3.432, 3.532, and 3.632 kHz, respectively. Structures of the ATSs are the same as those in Fig. |