Sound-cloaking acoustic metamaterials are on the way

April 23, 2012

In simulated data, a sound wave impinging from the bottom gets redirected to the right by a triangular prism made of an acoustic metamaterial. If this were ordinary refraction, the wave would be deflected somewhat leftward as it emerged from the prism. (Credit: Z. Liang and J. Li/Physical Review Letters)

New materials that have the potential to create acoustically shielded environments may be on the way, Ars Technica reports.

In the latest development, researchers have shown how creating materials that have meandering paths for sound waves can result in a negative acoustic index of refraction.

More importantly, these materials may actually be manufacturable and work for sound waves in air — the stuff we might consider noise.

Simulations confirm that metamaterials composed of such channels have unusual properties that let them refract sound in the “wrong” direction and could improve ultrasonic imaging.

Ref.: Zixian Liang and Jensen Li, Extreme Acoustic Metamaterial by Coiling Up Space, Physical Review Letters, 2012, [DOI: 10.1103/PhysRevLett.108.114301]