The New Journal of Physics published the results of research by scientists who managed to make a three-dimensional object invisible when viewed in the microwave range.

In the course of the experiments, a metal cylinder 18 cm high was covered with a centimeter layer of the so-called plasmonic metamaterial. Metamaterials are materials whose properties depend primarily not on the composition, but on the structure of the substance. Plasmonic materials are materials in which their own particles, plasmons, or quanta of free vibrations of an electron gas, behave in an unusual manner.

A feature of the coating was that the scattered and reflected types of radiation were reflected from each other. As a result, the object became “invisible” to waves. Experiments have shown that the test sample has the best invisibility properties at a radiation frequency of 3.1 GHz. Subsequently, the results of practical studies were confirmed by means of computer simulations.

According to the researchers, the properties of the plasmonic metamaterial make it possible to hide the object even in the optical range. Experience has also shown that the actual size of objects that can be hidden depends on the wavelength of the electromagnetic radiation.

In 2009, two groups of physicists already announced that they were able to obtain special materials that become invisible in the infrared wavelengths. The experiments were based on the fact that the radiation had the property of bending around the test specimen placed inside this radiation. Then physicists used silicon in their experiments.