Acoustic Analogue of Bloch Oscillations and Resonant Zener Tunneling in Ultrasonic Superlattices

TL;DR

This paper demonstrates acoustic Bloch oscillations and resonant Zener tunneling in ultrasonic superlattices, revealing wave phenomena analogous to electronic behaviors in semiconductors.

Contribution

It introduces an acoustic analogue of Bloch oscillations and Zener tunneling using water cavities and polymer layers, a novel experimental realization.

Findings

Observation of time-resolved acoustic Bloch oscillations.

Resonant Zener-like transmission enhancement at specific cavity gradients.

Establishment of an acoustic Wannier-Stark ladder analogy.

Abstract

We demonstrate the existence of Bloch oscillations of acoustic fields in sound propagation through a superlattice of water cavities and layers of methyl methacrylate. To obtain the acoustic equivalent of a Wannier-Stark ladder, we have employed a set of cavities with different thicknesses. Bloch oscillations are observed as time-resolved oscillations of transmission in a direct analogy to electronic Bloch oscillations in biased semiconductor superlattices. Moreover, for a particular gradient of cavity thicknesses, an overlap of two acoustic minibands occurs, which results in resonant Zener-like transmission enhancement.