Invisibility cloak hides bumpy 3D object from visible light

If only there were a “Harry Potter” invisibility cloak you could throw on, the ideal accessory for stalkers and the socially inept.

If the cloak, which is now on the microscopic level, were big enough, “You could cover a tank with it and make it look like a bicycle”, said Zhang. The USA military had come close to developing technology that could realize this fantasy, but they never really got as close as researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory recently have.

“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. According to them the technology underlying their “ultra-thin invisibility “skin” cloak” can be adapted to the macroscopic level. “It is easy to design and implement, and is potentially scalable for hiding macroscopic objects”.

Objects are visible to us because a small portion of the light that hits them is scattered in the direction of our retinas.

Now, we have to know that this invisibility cloak has only been tested using small objects so far, meaning it’s not officially proven that it will work in the same way that Harry Potter’s did, concealing entire bodies as needed.

From this observation, the team conceptualized a way to scatter the incoming light with a very thin metamaterial that will allow its physical structure to manipulate light without regards to its chemical composition.

Light reflects off the cloak (red arrows) as if it were reflecting off a flat mirror in this 3D illustration of a metasurface skin cloak made from an ultrathin layer of nanoantennas (gold blocks) covering an arbitrarily shaped object is shown in this handout image courtesy of Xiang Zhang group on September 17, 2015. Previous invisible cloaks ended up to be bulkier than the object that they were trying to hide . However, while successful in bending light around an object, these devices also disturb the phase of the electromagnetic wave; so, while the object remains hidden as no light is reflected off it, the cloak itself can still be spotted through specialized instruments.

There are a number of limitations to this invisibility cloak.

It is interesting to know that the cloak is able to function on its own and requires no power source or camouflage, earlier technique used for invisibility purposes.