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).

Chen Di-Chao, Zhu Xing-Feng, Wei Qi, Wu Da-Jian
       

(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. 5.