Reconfigurable Acoustic Metalens with Tailored Structural Equilibria

TL;DR

This paper introduces a reconfigurable acoustic metalens using bistable origami units, enabling dynamic control of sound focusing points through manual configuration changes, advancing versatile acoustic wave manipulation.

Contribution

It presents a novel origami-based design for a reconfigurable acoustic metalens with bistable states, allowing tunable sound focusing without complex electronic systems.

Findings

Successfully demonstrated on-demand reconfiguration of focal points

Achieved off-axis sound focusing through structural adjustments

Validated the concept with theoretical and experimental results

Abstract

The ability to concentrate sound energy with a tunable focal point is essential for a wide range of acoustic applications, offering precise control over the location and intensity of sound pressure maxima. However, conventional acoustic metalenses are typically passive, with fixed focal positions, limiting their versatility. A significant obstacle in achieving tunable sound wave focusing lies in the complexity of precise and programmable adjustments, which often require intricate mechanical or electronic systems. In this study, we present a theoretical and experimental investigation of a reconfigurable acoustic metalens based on a bistable origami design. The metalens comprises eight flexible origami units, each capable of switching between two stable equilibrium states, enabling local modulation of sound waves through two distinct reflection phases. The metalens can be locked into specific symmetric or asymmetric configurations by manually tailoring the origami units to settle either of the two states. Each configuration generates a unique phase profile, focusing sound energy at a specific point. This concept allows the focal spot to be dynamically reconfigured both on and off-axis. Furthermore, the approach introduces a simple yet effective mechanism for tuning sound energy concentration, offering a solution for flexible acoustic manipulation.