Scientists have created the first ‘cloak’ to make an object invisible in three dimensions by bending light around a micrometre piece of gold - a bit like water flowing around a rock in a stream.
As we reported our recent feature ‘Nothing is Impossible’, 2D invisibility has already been achieved. Perforating silicon with tiny holes to reflect light travelling in one direction makes objects behind it vanish – but only if viewed from one angle.
Now, scientists in Germany have created a photonic metamaterial which offers invisibility from all sides.
The cloak hides an object under a reflective ‘bump’ made of tiny rods of polymer crystal. Normally, the raised bump produces a distortion in the reflected image. But by changing the thickness of the crystal rods, researchers found they could alter the ratio of air to polymer, adjusting how the bump reflects light. By tailoring the bump’s refractive index, its curved surface appears to be flat – as though you’re looking at a mirror.
The research used light wavelengths slightly longer than those we can see, but it’s a huge step forward. We’re still a long way from the dream of a fully-functioning invisibility cloak, but what would top your to-do list if you could just disappear?
1) Sneak into MI5
Come on, wouldn’t you? You couldn’t share any of that juicy national security info, but a peak into spy HQ has to be up there.
2) Do a Harry Potter
Whether your fan dressing gown is Gryffindor or Hufflepuff, enhance your wizarding experience with the ultimate piece of fan merchandise. Much better than throwing some tin foil or a bin liner over yourself.
3) Be spooky
We’re talking cheeky, not just plain evil. More Casper the Friendly Ghost than the things out of Poltergeist. Everyone appreciates a hilarious hovering plate or the odd missing sock.
4) Spy on family and friends
Who knows what your parents/girlfriend/’best friend’ gets up to when you aren’t around. If it’s something bad, at least you’ve got number 3 to get them back.
5) Dodge dodgeball
The movie was good; the sport is terrifying. If you’re a 13-year-old American who can’t get up enough speed to avoid bruises, whip on the cloak and have a nap in the corner.
6) Avoid being ‘chosen’
When your boss scans the room for who to send to a ghastly conference, slip the cloak on and you’ll be out of sight, out of mind. If questioned, say you nipped to the loo.
7) Stow away
Disappear without a trace to a sunny paradise. Keep the cloak on to avoid having to act as a Sat-Nav for lost tourists.