Thanks to the combined efforts of researchers from the University of Sussex and Bristol, we have a new metamaterial that has the potential to revolutionize the way the world makes use of sound. The new supermaterial supposedly has the capacity to bend, shape and focus sound waves that pass through it.
A metamaterial is an artificially created material that is designed to challenge physical reality and defy the laws of nature. Some of the notable metamaterials invented include a kind of invisibility cloak (much like the one Harry Potter has) that can capture and bend light waves, and a heat-reflecting wrap that can provide cooling without the need for electricity. There’s also graphene, of course, and the still hypothetical 1D boron chains.
The latest addition to this growing list of super-metamaterials doesn’t even have a name yet, but it has very promising applications, especially in the field of medicine (particularly medical imaging) and entertainment.
To assemble the metamaterial, the team made use of lots of small bricks, each of which can ‘coil up’ space. This space coiling is what makes slowing down of sound possible, which in turn allows transformation of the sound waves into whatever type of sound field is needed. The size of the bricks and the number of layers that make up a grid can be scaled up or down so it can perform a variety of functions. And the bricks can be made of any kind of rigid material. For this version, the team used polymer.
As Professor Sriram Subramanian, head of the Interact Lab at the University of Sussex, explained to MailOnline: “Each brick has a labyrinth structure which is carefully designed to delay the time it takes for sound to go through the structure. When sound enters the brick on one-side, it has to go through this maze of obstacles created by the labyrinth structure, and comes out on the other side. The labyrinth is designed carefully to create a set of bricks that all introduce different delays. Then by assembling this mosaic of bricks we can shape the sound field as desired.”
Among the applications being envisioned for this metamaterial include using small versions that can be fitted to a patient’s body to focus high intensity ultrasound and target tumors deep within; and using large or layerd versions to focus sound waves to a specific location, then create an audio hotspot or make improvements on other kinds of audio technologies. Either way, the layered brick can be made to fit on any existing loudspeaker technology. More importantly, it can be made quickly and inexpensively.
Because this is only the beginning, there’s wide room for improvement. According to the team, the material can be 3D printed, and layers of it can be made dynamically reconfigurable — for example, they can be formed into sheets that can control sound. As the team said in a statement they issued, this would then allow for the creation of affordable imaging systems that can be used for ‘medical diagnostics and crack detection.’
The research has been published in the journal “Nature Communications“.
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