Since long before Harry Potter, scientists have been searching for a way which can allow things to pass us by unnoticed. The invisibility cloak which features in J.K. Rowling’s books may seem magical and otherworldly, but in fact devices which have the effect of making objects completely disappear are much more tangible than you’d think. While they may not look like a silky blanket, cloaking devices are very effective at manipulating signals and jamming detectors so as to obscure the truth about their location.
So there it is, we’ve done it. We have successfully created magic and are able to hide enormous ships or helicopters from being spotted by the enemy – haven’t we?
Well, not exactly. The perfect cloaking device is still just a theoretical concept. Camouflage paint is often applied to try and confuse the eye, “stealth” coatings are used to hide from radar, while cooling techniques are employed to reduce the amount of infrared emission coming from the object trying to stay hidden. However, while these techniques are effective at helping to disguise ships and aeroplanes, we can hardly call them invisible. It is hoped the answer lies in the development of metamaterials – materials which possess properties not found in nature.
The development of such materials has huge implications for lens and invisibility devices. The idea of cloaking devices is to create a material which can take an incoming signal, say visible light, and then send it on its way without any interruption from the cloaked object. If you could create a material which can do this effectively enough, it will trick any detectors into thinking there is no object to be seen, since there is no radiation signal to be detected. In theory it’s possible, but there are many obstacles blocking the way.
So there it is, we’ve done it. We have successfully created magic and are able to hide enormous ships or helicopters from being spotted by the enemy – haven’t we?
Well, not exactly. The perfect cloaking device is still just a theoretical concept. Camouflage paint is often applied to try and confuse the eye, “stealth” coatings are used to hide from radar, while cooling techniques are employed to reduce the amount of infrared emission coming from the object trying to stay hidden. However, while these techniques are effective at helping to disguise ships and aeroplanes, we can hardly call them invisible. It is hoped the answer lies in the development of metamaterials – materials which possess properties not found in nature.
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| The electromagnetic spectrum covers all wavelengths of radiation, from radar to visible light to x-rays and gamma-rays. Until last year we could only hide things from very specific parts of the electromagnetic spectrum, in some cases by making the object more visible in other parts of the spectrum. Image credit: NASA (public domain) |
