Incredible as it may sound, a counter-light beam could be used to make objects disappear optically. A precise counter-radiation causes an optical cloaking effect in the laboratory. In Greece, researchers have developed a theoretical basis for this cloaking trick, which could make objects disappear without the use of metamaterials or complex lenses. The cloak compensates for the light scattering on the object by a precise counter-radiation, allowing the light to pass through undisturbed and making the object invisible. The researchers are now planning to conduct experiments to test the theory.
According to the laws of physics, materials with internal irregularities scatter an incoming light beam in all directions. If the irregularity is compensated for by a precise light beam, the wave can penetrate undisturbed. In the laboratory, exotic metamaterials are used to bend light around an object so that it disappears. However, an invisibility effect can also be achieved through special resonance effects or a specific arrangement of lenses. The team led by Konstantinos Makris of the University of Crete has now developed a further cloaking technique. They were able to make an opaque material invisible to a second light beam by irradiating it with only one light beam of a certain wave pattern.
The researchers have been working for years to find a way to overcome wave scattering, for example, using metamaterials or objects that emit light themselves. The goal is not to redirect the light wave but to control the light beam straight through an object, as if it were not there. Makris explains that this is possible with special wave technology and certain materials. The wave pattern compensates for the material’s refraction. If the precise pattern of the internal irregularities is projected onto the material, the scattering can be practically eliminated. A vertically oriented light beam can then pass through the material without loss. The researchers are confident that this technology will open up entirely new possibilities in active camouflage.
