Spin-induced lateral acoustic forces on chiral and achiral particles

Abstract

Acoustic spin enables intriguing chiral sound-matter interactions, yet its mechanical consequences remain much less explored. Here, we demonstrate spin-induced lateral acoustic forces on chiral and achiral particles coupled to a substrate. Under plane-wave incidence, left- and right-handed chiral particles scatter fields with opposite acoustic spin that selectively couple to counterpropagating guided waves, generating lateral forces of opposite signs on the enantiomers. The lateral forces can also be realized for achiral particles by employing acoustic vortex-beam illumination. We experimentally validate the spin-dependent excitation of guided waves and lateral forces. Our results provide a route to spin-controlled acoustic manipulation and chirality-selective particle transport.