Fig. 3: The experimental demonstration of elastic-wave circulator.

a The setup of experimental platform. b The experimentally measured normalized out-of-plane amplitude \(|\bar{w}|\) at 11.2 kHz when the source is placed near port I, port II and port III, respectively. The black solid lines in the circulators represent the maximum of \(|\bar{w}|\) at different azimuths, and the red box regions are selected for the calculation of contrast ratio \(\eta\). c The measured normalized out-of-plane displacement \(\bar{w}\) in time domain. P1 ~ P6 are selected in the centers of six ports in (b). The blue, orange and gray lines correspond to the inputting near port I, port II and port III, respectively. d Numerically simulated (FEM) and experimentally measured (EXP) contrast ratio \(\eta\) as the function of frequency. The baseline of extremely high asymmetry is \(\eta=6\), above which highly asymmetry can be obtained from 11 to 13.5 kHz.