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Hyperlens sharpens sight with sound


A new hyperlens developed by scientists could lead to clearer ultrasound images (Source: iStockphoto)

Scientists have developed a new hyperlens that could soon give expecting parents high-definition baby pictures as well as provide ship captains incredibly accurate maps of the sea floor.

The research, published in the latest edition of Nature Materials, makes high-resolution ultrasounds and sonar imaging now possible.

"The images you get when you try to look at unborn babies [with an ultrasound] are pretty fuzzy. You can see an arm, but you can't clearly see facial structures," says author Dr Xiang Zhang of the University of California, Berkeley in the US.

"With this new technology, we will be able to resolve a baby's face before it's born."

The brass hyperlens developed by Zhang is made of 36 fins, spread out in a half circle like a handheld fan.

Each fin, roughly 20 centimetres long, compresses and magnifies incoming sound waves, making it easier to tease out the image of a tiny nose or the line of a check bone from an ultrasound.

Brass lens

Zhang made his hyperlens from brass for easier production. However, a hyperlens could be produced from many other more durable materials, including steel.

That durability will be important for another use as well. Deploying a hyperlens underwater could give submarines a detailed view of underwater geographical features or incoming enemy submarines.

A hyperlens is part of a larger group of materials known as metamaterials. Unlike normal materials, which derive their physical properties from their chemical components, metamaterials derive their physical properties from their physical structure.

These structures need to be much smaller than the wavelength they intend to manipulate. Scientists from all over the world have relentlessly created ever-smaller structures to manipulate ever shorter wavelenghts of light.

Sound waves

Metamaterials can now manipulate an entirely different kind of wave- sound waves.

Unlike an electromagnetic wave, which doesn't need a medium to propagate through, sound waves need some physical material such as air or water.

"These are really different phenomena," says Viktor Podolskiy, a physics professor at Oregon State University studying metamaterials. "But the equations that govern both their actions are very similar."

This new metamaterial is the first acoustic hyperlens Podolskiy has heard of. Scaling up its production for commercial use instead of laboratory experiments will likely take years, he says.

Metamaterials can already be found in several commercial devices, including wireless routers and a new cell phone from LG.

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