An ultra-thin invisibility skin that can make objects disappear in Harry Potter style has been developed by American researchers.
Although the technology so far only works on very small objects, the team from the US Department of Energy's Lawrence Berkeley National Laboratory believes they could eventually be able to create a larger version.
The approximately 80 nanometre-thick material consists of gold ‘nanoantenna’ blocks that interfere with the normal scattering of light waves. The material adheres to the object and when the polarisation of the nanoantennae is switched on, the object becomes optically undetectable.
So far, the method - described in the latest issue of the journal Science - has only been demonstrated on objects the size of a few cells.
“This is the first time a 3D object of arbitrary shape has been cloaked from visible light,” said Xiang Zhang, director of Berkeley Lab’s Materials Sciences Division. “Our ultra-thin cloak now looks like a coat. It is easy to design and implement and is potentially scalable for hiding macroscopic objects.”
The invisibility material, or metamaterial, has been carefully engineered and is a product of several years of research.
Metamaterials are artificial nanostructures with electromagnetic properties that can’t be found in nature. With features smaller in size than the wavelength of light, the metamaterials can effectively reroute incoming light waves.
In an experiment described in Science, the researchers coated an irregularly shaped object about 1,300 square microns in size with the metamaterial. Once the polarisation was turned on, the object reflected light in the same way as a flat mirror.
Although the technology represents a major step forward compared to earlier rather bulky and impractical invisibility cloaks, there are still limitations. For example, the object can’t be moved around at all without breaking the invisibility.
The researchers believe the invention can pave the way for many applications, for example in security encryption or hiding the layout of microelectronic components.
Zhang’s team has previously demonstrated other intriguing capabilities of metamaterials. They engineered metamaterials that can bend light backwards or curve its path.
The ability to manipulate the interactions between light and metamaterials offers interesting prospects for technologies such as high resolution optical microscopes and superfast optical computers.
Watch the material in action: