Acoustic imaging by three-dimensional acoustic Luneburg meta-lens with lattice columns

TL;DR

This paper presents a 3D acoustic Luneburg meta-lens made of lattice columns that can focus sound omnidirectionally across a broad frequency range, enhancing acoustic imaging and focusing capabilities.

Contribution

It introduces a novel 3D acoustic meta-lens design with lattice columns, demonstrating improved omnidirectional focusing and imaging performance over traditional 2D lenses.

Findings

Successful simulation and measurement of 3D focusing performance

Confirmed omnidirectional sound pressure focusing

Potential for improved acoustic device performance

Abstract

A three-dimensional acoustic Luneburg meta-lens has the advantage of refracting sound waves for all incident angles and focusing higher sound pressure compared to a two-dimensional lens. The lens made of plastic with a diameter of 120 mm was designed with thousands of lattice column-shaped meta-atoms to maintain its three-dimensional shape. The lens's three-dimensional focusing performance and acoustic imaging were simulated and measured at the frequency range of 5 kHz ~ 20 kHz. The omnidirectional property was confirmed by rotating the lens to change the incident angle and measuring the sound pressure. The development of these spherical Luneburg meta-lenses is expected to improve the performance of devices that require acoustic focusing.