How Warping Sound Waves Could Boost Ultrasound Imaging

Brian Buntz

February 27, 2014

2 Min Read
How Warping Sound Waves Could Boost Ultrasound Imaging

Airborne sound waves can be warped using a device known as an acoustic field rotator made of metamaterials. Researchers from across the world have tapped metamaterials to develop everything from invisibility-cloak like devices to superlenses.

This, however, represents the first time that metamaterials have been used to warp sound waves in a manner to how they've been used to bend electromagnetic or liquid waves.

The scientists, based in China and in the United States, suspect that the ability to use metamaterials to precisely tune acoustic wavefronts could improve medical ultrasound devices, potentially boosting their contrast as well as the accuracy of ultrasound-based diagnosis of abnormal tissue.   

The researchers describe the significance of their accomplishment in Applied Physics Letters:

We have theoretically designed and experimentally realized a metamaterial-based acoustic field rotator that can be tailored to rotate the acoustic wavefront by a certain angle. For airborne sound, the designed field rotator simply comprises an array of identical plastic plates. The rotation effect and the broadband functionality of the resulting device have been demonstrated both numerically and experimentally. Excellent agreement is observed between the numerical simulation and experimental results. The realization of acoustic field rotator has offered possibility of acoustic manipulation and may have potential application in situations in need of special controls of acoustic wave.

The team plans to refine the design of the acoustic field rotator, which they state is still "the simplest proof-of-concept device." Future designs could further improve the ability to manipulate sound waves.  

It is not, however, the first time that researchers have stated that metamaterials could be used to boost ultrasound. Several years ago, for instance, scientists based in Berkeley, CA and Spain proclaimed that metamaterials could be used to boost ultrasound resolution by a factor of 50.

Other researchers have explored using metamaterials to convert ultrasound waves into optical signals.

Brian Buntz is the editor-in-chief of MPMN. Follow him on Twitter at @brian_buntz and Google+.

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