Figure 1. (IMAGE) Science China Press Caption Acoustic spin. (a) 90-degree phase difference between the two particle velocity components resulting in a rotating polarization. (b) Acoustic spin in the interference of two perpendicular acoustic beams. Credit ©Science China Press Usage Restrictions Use with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.