An invisibility screen has been developed that bends light to make objects disappear. It could be used to hide tanks and troops or to remove intrusive buildings from the landscape.
A recent video by , a Canadian camouflage company, shows the screen in action. Initially, it appears as though there is an empty desk behind a clear screen, but as the camera moves around, it becomes apparent that the screen is actually hiding a helmet.
Hyperstealth has been developing its so-called Quantum Stealth material since 2011, but its claims were impossible to confirm. Now, the company has applied for patents and published more details about their technique.
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Despite its name, Quantum Stealth is based on old technology rather than modern metamaterials. It uses rows of cylindrical lenses on a flat sheet, commonly used for novelty pictures that show different images from different angles. A particular arrangement of these lenses can create an invisible zone. It works in both the infrared and visual range.
鈥淟ight is refracted on the material in such a way as to merge parts of the background while leaving other parts in place, creating a neutral zone to hide a target,鈥� says Guy Cramer at Hyperstealth.
The technique requires a few centimetres of separation between the target and the material. It also doesn鈥檛 always work from every angle and actually magnifies the object from some positions. Cramer believes the team can minimise this effect in future versions.
The screen isn鈥檛 flexible enough to be worn, but it is cheap. Material for a shield large enough to hide a person costs about $5, says Cramer.
There are several versions of the screen in the new videos, including a portable shield, a large sheet and a cylinder that conceals objects inside. A tank or other vehicle could be hidden from aerial observation under a sheet of the material, and a large-scale version could hide chimneys, masts or other unsightly structures.
This technique has been around since the 1920s, according to Cramer. 鈥淲hy no one figured out this technique before is beyond me,鈥� he says.
鈥淭his is a limited, but useful, form of invisibility,鈥� says John Pendry at Imperial College London, who has worked on the mathematics behind invisibility cloaks, which use advanced metamaterials to bend light and conceal objects but are聽currently confined to the laboratory.
Robert Bunker at the US Army War College鈥檚 Strategic Studies Institute says the material looks highly effective, but that countermeasures are likely to be developed. Artificial intelligence will be developed to sense the light bending that is created in the surrounding space, he says.
