Sound non-reciprocity based on synthetic magnetism

TL;DR

This paper demonstrates a non-reciprocal acoustic system using synthetic magnetism through spatiotemporal modulation, achieving high isolation and forward transmission, advancing acoustic nonreciprocal device technology.

Contribution

It introduces a novel acoustic system with phase-correlated modulations creating synthetic magnetic flux for non-reciprocal sound transport.

Findings

Achieved 45-dB isolation ratio in acoustic transport.

Demonstrated frequency-preserved unidirectional transport.

Controlled transport properties via dynamic and static couplings.

Abstract

Synthetic magnetism has been recently realized using spatiotemporal modulation patterns, producing non-reciprocal steering of charge-neutral particles such as photons and phonons. Here, we design and experimentally demonstrate a non-reciprocal acoustic system composed of three compact cavities interlinked with both dynamic and static couplings, in which phase-correlated modulations induce a synthetic magnetic flux that breaks time-reversal symmetry. Within the rotating wave approximation, the transport properties of the system are controlled to efficiently realize large non-reciprocal acoustic transport. By optimizing the coupling strengths and modulation phases, we achieve frequency-preserved unidirectional transport with 45-dB isolation ratio and 0.85 forward transmission. Our results open to the realization of acoustic nonreciprocal technologies with high efficiency and large isolation, and offer a route towards Floquet topological insulators for sound.