Harry Potter’s invisibility cloak is one accessory every Muggle would like to include in their wardrobe. For those of you who are not familiar with Harry Porter terminology, Muggles is the term, magic folk use to call non magical folk (and invisibility cloak is self-explanatory). We Muggles may not possess magical powers to conjure an invisibility cloak, but we surely have technology and genius, to fashion ourselves one.
A simple principle exists behind the theory of invisibility. We can only see objects which reflect light incident on them, so in order to make any material or object invisible the reflection of light should be disabled. This is a simple concept but its execution is extremely difficult, and until now it was considered almost impossible. The phenomenon was reality with the use of artificially structured materials known as “metamaterials”.
Metamaterials are unique materials which defy the natural law of absorption of light by materials which are considered to be written stone. The light can only pass around this material, not through it. Now, how are these materials actually made? These materials are assembled from photonic crystals to wires and foam. These are then scaled at level smaller than the wavelength aimed for manipulation so as to force the light to bend around the material. The waves which are aimed at manipulation usually include microwave, infrared or visible light. To change the behaviour of this material scientists have realised that the shape of the material plays a major role besides the material itself. The metamaterials used to make a cloak of invisibility was observed to show images behind the cloak donner but the image was blurry and darkened. Scientists then realised that sharper edges did a better job of invisibility and hence by further experimentation they created a diamond cloak with the corners matching the required properties carefully.
Even though the little tweaks enhanced invisibility offered by this super impressive material this was not the end of obstacles. First obstacle was that this cloak worked only in one direction. The second was tuning it to match the required wavelengths. With further experiments if these issues are solved then we get one step closer to making our own Hogwarts here!
What would we use all this invisibility for? Other than fun stuff like playing pranks and hiding from your boss, this invention will play a vital role in military and telecommunication. Since invisibility can be the biggest asset for any army, metamaterial uniforms will find a place in the military. Other than this these metamaterials have the potential to join the wireless charging technology bandwagon. Several major industries have patents for these chargers and even though their working is kept under wraps, the usage of metamaterials has been emphasized abundantly. Besides these cool uses, the cloak of invisibility may also help in averting earthquakes and tsunamis. Even though this is a slightly more difficult goal to achieve, it is not impossible!