The invisibility cloak
We all remember reading about Harry Potter and his magical cloak , one that could render the wearer invisible. Just admit it folks , at some point in our lives we have all wanted to possess one. Just wrap it around and bingo you disappear. It’s the ultimate wardrobe necessity. Just think of the infinite opportunities that such an invisibility cloak lays open, be it spying on someone or entering any restricted area , the invisibility cloak comes with the ability to get away with almost anything and everything.
Well the good news for us muggles is that the magic of modern science has created something pretty similar to the invisibility cloak.It is still far from perfect though.They are bulky. Many of them working only with a certain bandwidth of light in which they are invisible and many which limit the size of objects to only microscopic ones.Yet it is definitely a giant leap forward. So for those of us muggles who aren’t nerds, here is how it works.There have been a number of different methods which have been used. And if you seek to get one there are a wide range of options to choose from.
One of the ideas that have been used to design the invisibility cloak is something called mantle cloaking. Now what’s that? This involves cancelling off all light rays bouncing off the object to be rendered invisible,thereby achieving an effect of overall transperancy. Again there are two ways to achieve mantle cloaking. Let us first look at the simpler option. Remember high school physics, how mirages occur.That’s exactly how this cloak works.It creates a similar sharp temperature gradient via electrical impulses to bend away light. The disadvantages of course being the heating effect.
Now coming to the more complicated method.This one involves metamaterials,structures smaller than the wavelength of light.A properly constructed meta material uide rays of light around an object — much like a rock diverting water in a stream.The catch: only works in two dimension.
Now that was all more of transformational optics or bending of light.The latest research in this field involves something called quantum cloaking.It is hiding an object from reality by reducing its probability of existence defined by Shrodinger’s wave equation to zero.Ok for those of us scared of that last line, what it basically means is trying to cheat reality to create the illusion of invisibility.This concept is still mostly theoretical and if successfully translated into reality it would be a major breakthrough in this field.
Modern technological marvels have bridged the gap between reality and sci fi.A lot of things that we take for granted presently may have been nothing short of a miracle for our ancestors.The future is promising and may be described as something straight out of a sci fi movie where Invisibility cloaks and time machines may as well be a common sight.Looking forward to being invisible some day……