Scientists unveil invisibility cloak big enough to hide a human or a satellite orbiting earth – so long as you look at it from one direction only
- Scientists have shown how to steer light around objects using mirrors
- Device could be used to hide a human or a satellite orbiting Earth
- Design has been used for years but not on such a large scale
By JAMES RUSH
PUBLISHED: 11:14 EST, 7 June 2013 | UPDATED: 11:14 EST, 7 June 2013
Scientists have unveiled how to make invisibility cloaks that are big enough to hide a human – or even a satellite orbiting the earth.
As the interest in creating Harry Potter-style cloaks continues to grow, researchers in America have shown how a simple trick used for years by magicians can create the desired effect.
Using conventional lenses and mirrors, the scientists are able to steer light around the region of space they want to hide.
Over the last ten years scientists have investigated two main ways of creating invisibility cloaks, according to the MIT Technology Review.
‘Transformation optics’ involves bending light around an object to make it look as if it wasn’t there.
Metamaterials meanwhile are synthetic substances which can also achieve the same aim through using certain optical properties.
Neither technology is perfect, but John Howell, from the University of Rochester, New York, and Benjamin Howell have now shown how to build a device big enough to cloak a person using an array of lenses and mirrors to steer light around a region of space.
The Howells said: ‘This volume is sufficient to cloak a human, albeit with not as much convenience as Harry Potter’s cloak.’
The design has been used for years but the Howells have said they wanted to point out how easily it could be scaled accordingly.
A major caveat in the design is that they only work in one direction – viewing the cloaks from any other pint of view reveals the device.
But the Howells have said: ‘The devices may have value, for example, in cloaking satellites in mid to high-Earth orbit.’
Earlier this week, scientists unveiled a ‘time cloak’ which bends light to tear holes in time itself.
The device could have important implications for sending secret messages via fibre optic cables.
It can hide a continuous stream of events at telecommunications data rates – much quicker than a similar invention unveiled last year.
Researchers used equipment known as modulators to make the holes by bending light, Nature reported.
Although a long way off the fictional ‘invisibility cloaks’ featured in Star Trek and the Harry Potter films the concept could have practical applications to conceal messages.
OPTICAL ILLUSION- A QUICK GUIDE
At its most basic level, a cloaking device simply guides light around an object as if the object wasn’t there.
An example of technology that does this is an endoscope which is used to image hollow organs in the human body.
Much of the research into invisibility cloaks to date has focused on the use of metamaterials.
These are synthetic substances that can guide light using their unique optical properties.
Instead of using complex meta materials to steer light, the researchers at Rochester University did the same job with off-the-shelf lenses and mirrors.
Their array of lenses or mirrors was shown to steer light around the region of space they want to hide.
This means their cloaks were simple to build and easy to scale. Mirrors, in particular, can be made almost any size.
The researchers demonstrated cloaking over the visible spectrum with cloaking regions exceeding 106 mm3.