Invisibility can be achieved through manipulation of light - VIDEO PDF Print E-mail
Friday, 28 November 2014 15:36

Invisibility - like time travel, teleportation, levitation and sverhskorost - is the subject of science fiction since its inception. Among the best-known examples - that invisibility, which was used by the Romulans in "star Trek," Harry Potter by a cloak-and-Frodo to get to Mordor. Hundreds, if not thoUSAnds of references invisibility found in books and movies. For many years, scientists have come up with interesting ways to hide objects from view, except that in these cases the process was much more complicated than the science fiction shows.

Before we can talk about, so to speak, the scientific cloak, we need to understand the relationship between light and physical objects. Believe it or not, but this attitude is quite simple. When we look at something - be it an apple or a car - what we see is reduced to a wavelength of light that is reflected and absorbed by the object.

In the case of the Sun, for instance, its white color due to the fact that it absorbs all wavelengths of light. However, off the bat, most people would say that the Sun is actually yellow (but it is quite another). Given this, it would be superfluous to ask whether it is possible to do so, to hide the true color of the object or even make it invisible?

The answer is more interesting than it seems at first glance: it is possible. French scientists recently announced that they have found a way to manipulate light so that the tiny opaque object is completely transparent to the human eye. Although it sounds simple, it is actually much more complicated.

The technique used by scientists, based on quantum effects. Things such as Rayleigh scattering, have taught us that the particles of light live stormy life, continually confronted with the fact that the path through space-time. When they come into contact with molecules and other particles of matter, their components, ie photons bounce in different directions at odd angles. Other difficulties arise when we add additional interaction of atoms or molecules in the equation. In such an environment, called quantum emitters, and they are extremely important for a promising field of quantum technologies.

When one light source is in contact with the other emitter, the light bounces and shows changes in the electromagnetic field, resulting in scattering of photons generating more complex wave patterns. Still need to not forget about the dipole - or quantum emitters with positive and negative side. This feature, which is a result of the fact that the emitter has uneven distribution of electrons, can have a serious impact on the electromagnetic field. The electromagnetic field of each radiator is important.

Ultimately, all this often gives rise to what is called a dipole-dipole interactions: a combination of things that intensively scatter light. And studies have shown that this effect can be used to manipulate the light reflected from the surface.

Quantum emitter (represented as blue disk) interacts with the electromagnetic field. Physicists use the dipole-dipole interactions in such quantum emitters to make opaque objects transparent.

More specifically, scientists are using a new technique called DIET (dipole-induced electromagnetic transparency) to prevent bouncing of light reflected from the surface of a particular wavelength that makes an object essentially transparent in the visible range.

"The importance of our work lies in the discovery that a very slender appearance (DIET) can be used to control the propagation of light in optically active media - said co-author Eric Harron, a professor of the University of Paris in Orsay, France. - We have shown how the light is scattered in the nanometer system, and this effect can be controlled to make the object transparent opaque at any given frequency. "

The whole point of the work that scientists need to repeat his success as an example of the object more than two atoms in diameter (for reference, it is extremely small when compared with macroscales the world in which we live). Nevertheless, they are confident that not only will be able to do this with large objects, but also to deceive our eyes, not only to make an object invisible, and dye it a different color altogether.

Their work also sheds light (literally) on the ways in which we can greatly slow down the light or even freeze it. In the first case, this is done by changing the path of photons by interaction of the particles with the medium. The advantages of such a breakthrough too numerous to list, but certainly - ahead is still a lot of work.

"Now our goal is to move to a multilevel DIET atomic or molecular system - says Harron. - Each transmitter will behave as a series of oscillating dipoles, thus opening a number of windows of transparency that will allow us to conduct a more flexible strategiyumanipulyatsy.

Also, scientists are exploring methods of slow light based on their developments.



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