A revolutionary discovery made by a group of physicists from the University of Technology in Karlsruhe in Germany. Scientists under the leadership of the famous physicist, Professor Tolga Erginin presented their invention - a metamaterial with a negative refractive index of electromagnetic waves. Created on the basis of this material, the invisibility cloak allows you to hide objects in three dimensions with an angular view from 0 to 60 degrees. The basic idea of metamaterials is based on forcing streams of light waves to move in the way they do in the air. That is, the viewer must create the illusion of the absence of barriers.
The design itself is a frame that consists of special polymer blocks located directly above each other, the size of which is estimated at several hundred nanometers. The device makes it possible to make an object invisible with a size less than 1,5 micrometer, located on a flat surface.
In theory, a similar special masking technology was proposed in the 2008 year, but it was only now possible to put it into practice. The novelty contains many ideas previously used to create an “invisibility cloak”, which was supposed to reflect and refract light wave flows in a special way and create the final result of transparency, hiding everything that is placed under it.
Initially, all similar ideas were based on the idea of working with light waves, however, scientists also found that these methods work with sound waves. At the base, in terms of hiding various objects, there is no difference between light and sound. In January, 2009, a group of scientists from the Duke Institute in Durham, North Carolina, USA, created a fabric that hides diverse objects in such a way that it is impossible to fix them with the support of microwaves.
Now scientists have created a design that hides the waves in the audible range. The device can hide sound waves in the range from 1 to 4 kilohertz. The amazing device operates with the help of folded plastic sheets in a certain order with permanent arrays of holes in them. According to the developers, at this point in time, their model is largely conceptual, because it works with a relatively dense frequency range, in addition, it does not allow to hide an object in a wide volumetric space - just under the device, if the sound wave flow is directed from the sides, device will not work. However, the developers noticed that their device will undoubtedly be of interest to a variety of customers - from directors of musical performances to the military, who will thus be able to hide underwater secret objects from sonars.
Scientists from the Singapore Center for Special Technologies - the Singapore-MIT Alliance (SMART) are actively involved in the development of the “invisibility cloak”. In particular, not so long ago, representatives of the center announced the creation of a device capable of hiding even huge objects from visual observation. His work is based on calcite crystals and uses visual anisotropy, giving the illusion of visibility through an object. According to scientists, in the near future such devices will become familiar objects and each person will be able to purchase them.
“When“ refraction ”of space, we can direct a ray of light so that its angle of reflection is equal to the angle of location, we see a similar refraction in a flat mirror,” said George Barbastatis, academician of optics and mechanical engineering, head of the design team.
George Barbastatis and his team combined two pieces of calcite into a certain “mirror configuration” in order to create an illusion. “We had the opportunity to use different materials, but the selected calcite gives the best combination of exhibiting high anisotropy and at the same time it is also available in relation to cost,” said the scientist.
At the same time, Barbastatis notes that it’s too early to talk about the device created as an absolute disguise. First of all, this is due to the fact that invisibility is provided only in two-dimensional space. Another problem is the inoperability of the device in a liquid medium, that is, if it is raining outside, it is impossible to hide an object from a visual observation.
It is obvious that such a rapid pace in the development of the “invisible cloak” will soon make possible what we previously knew only from fairy tales.