Spherical silicon particles as small as a few hundred nanometers, according to scientists, may be part of invisibility cloak, a device that allows you to hide various objects in the visible wavelength range. The principle of operation of such a cloak of invisibility can be explained by the fact that the electromagnetic wave to a meeting with the subject in a raincoat is no different from a wave after the meeting. To date, the most successful in masking objects achieved in the infrared part of the spectrum and a very narrow range.
The main role in these physical processes play a metamaterial having left-hand index of refraction. Composite materials called metamaterials whose properties are due to an artificial periodic structure. Metamaterials create difficulty is that the structure of the particle size should be commensurate with the wavelength, and this is most easily achieved in the infrared range, when it comes micrometer wavelengths.
The main component of invisibility cloak are crystals. A spherical silicon particles may play the role of resonators, which was successfully demonstrated after a series of experiments. In an article published on the official website of Cornell University, the researchers point out that from an economic point of view, the production of such areas is inexpensive.
American physicists of the University of Texas at Austin has previously presented the results of work to create a cloak of invisibility. But their technology is different in that they have created a thin strip of material to absorb the waves of the visible range of light, converting it into heat or radiation of the electromagnetic spectrum. Strips of material made from copper or silver. In carrying out experiments on the metal surface appear quasiparticles called plasmons: an effect of the collective oscillations of electrons. Scientists were able to use this effect to create a new, in their properties, the metamaterial.