Acoustic Analogues of High-Index Optical Waveguide Devices

TL;DR

This paper demonstrates how acoustic metamaterials made from subwavelength air-filled pipes can mimic high-index optical waveguides, enabling open, noise-manageable acoustic devices with broad applications.

Contribution

It introduces a novel acoustic metamaterial design that achieves high effective refractive index, allowing open waveguides analogous to optical counterparts, expanding acoustic device functionalities.

Findings

Acoustic metamaterials can mimic high-index optical waveguides.

Open waveguides enable new noise management and sensing applications.

Demonstrated practical acoustic waveguide implementations.

Abstract

High index optical waveguide devices such as slab waveguides, strip waveguides and fibers play extremely important roles in a wide range of modern applications including telecommunications, sensing, lasing, interferometry, and resonant amplification. Yet, transposing these advantageous applications from optics to acoustics remains a fundamental practical challenge, since most materials exhibit refractive indices lower than that of air for sound waves. Here, we demonstrate the relevance of acoustic metamaterials for tackling this pivotal problem. More specifically, we consider a metamaterial built from subwavelength air-filled acoustic pipes engineered to effectively exhibit a higher refractive index than homogenous air. We show that such medium can be employed to realize acoustic equivalents of dielectric slab or strip waveguides, and optical fibers. Unlike conventional acoustic pipes, our guiding approach allows the waveguide to remain open to the external medium, which opens a plethora of new opportunities in noise management, medical imaging, underwater communication systems, and sensing.