Sometimes advances in modern technology can be mistaken for magic. Exact science works instead of magic. One of the areas of research, the results of which could well serve as an illustration of the properties of "fairy attributes", is the development and creation of metamaterials.
From a purely physical point of view, metamaterials are artificially formed and specially constructed structures that have electromagnetic or optical properties unattainable in nature. The latter are determined not even by the characteristics of their constituent substances, but by their structure. After all, you can build houses similar in appearance from the same materials, but one will have excellent sound insulation, and in the other you will even hear the breath of a neighbor from the apartment opposite. What's the secret? Only in the ability of the builder to dispose of the funds provided.
Metamaterial / Public domain
At the moment, materials scientists have already created many structures, the properties of which are not found in nature, although they do not go beyond the physical laws. For example, one of the created metamaterials can manipulate sound waves so finely that they keep a small ball in the air. It consists of two lattices, assembled with bricks filled with thermoplastic rods, which are laid in a "snake". The sound wave is focused like light in a lens, and the researchers believe that this device will allow them to develop sound control to be able to change its direction, as now changing the path of a light beam using optics.
The ball is held in the air by a sound wave focused by a metamaterial / Illustration by RIA Novosti. A. Polyanina
Another metamaterial can rearrange itself. An object is assembled from it without the help of hands, because the change in shape can be programmed! The structure of such a “smart” material consists of cubes, each wall of which is made up of two outer layers of polyethylene terephthalate and one inner layer of double-sided adhesive tape. This design allows you to change the shape, volume and even rigidity of the object.
3D Shape-Shifting Material by Harvard University / Johannes Overvelde / Bertoldi Lab / Harvard SEAS
But the most amazing properties are optical metamaterials that can change the visual perception of reality. They "work" in the wavelength range that the human eye sees. It was from these materials that scientists created the fabric from which you can make an invisibility cloak.
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However, so far only a micro-object can be made invisible in the optical range.
The possibility of creating a material with a negative angle of refraction was predicted back in 1967 by the Soviet physicist Viktor Veselago, but only now are the first samples of real structures with such properties appearing. Due to the negative angle of refraction, the rays of light bend around the object, making it invisible. Thus, the observer notices only what is happening behind the back of the person wearing the “wonderful” cloak.
This is how the artist imagined the invisibility nanocloak / Xiang Zhang group, Berkeley Lab / UC Berkeley
The latest achievement in the creation of optical metamaterials belongs to Russian scientists from NUST MISIS. Moreover, the "ingredients" used the most common - air, glass and water. The work of scientists was awarded publication in one of the highest-rated journals in the world Scientific Reports by the publishing house Nature.
Alexey Basharin, Associate Professor, NUST MISIS, Candidate of Technical Sciences / NUST MISIS
“It is very expensive and difficult to study metamaterials in the optical range, each such sample can cost thousands of euros,” said Alexei Basharin, a researcher at the Superconducting Metamaterials Laboratory at NUST MISIS, Ph. D. “In addition, the likelihood of error when molding such a system is very high, even with the use of the most high-precision tools. However, if you create a larger-scale material, in which there will be not optical (400-700 nm), but radio waves (7-8 cm long), the physics of the process will not change from such scaling, but the technology of their creation will become simpler."
Studying the properties of the created structures, the authors of the work showed that this type of substance has several practical applications at once. First of all, these are sensors of complex molecules, since the latter, falling into the field of a metamaterial, begin to glow. In this way, even single molecules can be determined, which can potentially significantly affect the development of, for example, forensic forensics. In addition, such a metamaterial can be used as a light filter, separating light of a certain length from the incident radiation. It is also applicable as a basis for creating ultra-reliable magnetic memory, because the structure of the cells of the metamaterial prevents them from magnetizing each other and thereby losing information.