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Friday, August 1, 2014

Scientists use light to stitch ‘invisible’ nanoparticles together

12:20 AM


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Image: The University of Cambridge

Tuesday, 29 July 2014
A team working on invisibility cloak technology has come up with a new technique that uses light to thread long chains of nanoparticles into light-refracting material.

At the centre of this new technique are tiny blocks made from ‘metamaterials’ - a special type of artificial material engineered to have properties unlike anything found in nature. These nanoparticle building blocks are just a few billionths of a metre wide, and researchers from the University of Cambridge in the UK have figured out how to control the way light flows through them. 
Controlling the way light interacts with a material is a key element of any ‘invisibility’ technology, and these metamaterials have been designed to refract light in a direction that renders them invisible to the naked eye.
In order to do this, the researchers needed to 'stitch' the metamaterial nanoparticles together into several long strings, which they did by placing the metamaterials in some water and blasting them with an unfocused laser light. "These strings can then be stacked into layers one on top of the other, similar to LEGO bricks," they say in a press release. "The method makes it possible to produce materials in much higher quantities than can be made through current techniques.”
Now, what we really want to know is… when do we get our invisibility cloaks? The next step is figuring out how to build bridges between the nanoparticles so they can be produced in larger quantities. "There is a knack to doing this," says Katie Collins at Wired UK, "and it involves spacing the material blocks carefully and accurately using barrel-shaped molecules called cucurbiturils so that it's as easy as possible to retain control over the process."

The researchers published their results in the journal Nature Communications.

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