Invisibility cloak, that was developed in the U.S., Berkeley, the world’s first composite coating completely masking objects not only in the infrared, but also in the visible range.Invisibility cloak is based on the principle of a mirror. Because such coverage can not see what is placed under him, an outside observer remains ignorant of the subject nestled by cloak. Light skirts such subject. This effect is made possible by the presence of alternating refractive of the fabric. Such artificial materials called metamaterials.
Metamaterial developed at Berkeley, became a lining of transparent nanoporous silicon oxide layer, which was placed in a waveguide layer of silicon nitride. Refractive index for the lower layer of cloak of silicon oxide is lower than for the top, consisting of Si3N4.When in the waveguide were made nanoscale openings, surface acquired properties of a metamaterial.