Fig. 5: Experimental observation of acoustic-wave–kink interaction (kink control) in the KL chain.
From: Observation of mechanical kink control and generation via acoustic waves
a Single rotor assembly. Inset: a single polycarbonate spring. b Two rotors connected via polycarbonate springs. c Bottom view of the excited rotor. d Experimental setup with chain of 18 rotors configured as in (e). e Chain with kink centered at the 9th rotor (yellow arrow) with green and red arrows indicating the polarization vectors. The blue star marks the excited rotor (n = 1). f Normalized excitation function. g, h Selected experimentally measured (g) and simulated (h) spatiotemporal chain responses in terms of normalized total energy at each site. Green dashed lines denote the predicted wave packet center position based on the group velocity at the excitation frequency in the infinite homogeneous chain, while yellow solid lines indicate the fitted kink’s center position. Color bars are truncated for clarity. i, j Fitted kink’s center trajectories for different excitation amplitudes in experiments (i) and simulations (j). The driving voltages amplitudes in (i) were randomly chosen, with the upper and lower limits chosen based on when increased interplay with the excitation boundary and minimal kink motion was observed, respectively. The driving torque amplitudes in (j) were chosen based on a tri-linear equal spacing of torques, with the most dense spacing in the vicinity of 17.5 mN m.
