Physicists have succeeded in homogeneous cylindrical objects with a radius of 12mm and a height of 42cm completely invisible in the microgolflengtegebied. They got this for each other without the use of metamateriaalcoatings.
The complete study of the ITMO university in St. Petersburg in Scientific Reports. The method used is based on a new understanding of electromagnetic golfverstrooiing. To achieve the effect studied to the researchers, the light that is scattered by a water-filled glass cylinder.
The university writes on its website that in this way a natural phenomenon to be simulated, the so-called Mieverstrooiing. Mieverstrooiing is, for example, where to take in the atmosphere as the diameter of particles in the atmosphere is comparable to the wavelength of the scattered light. Dust, pollen, smoke and microscopic water droplets are common causes of Mieverstrooiing. In the study used the researchers water, whose refractive index can be changed by the temperature change.
It turned out that a high refractive index can be associated with two verstrooiingsmechanismen, in relation to the localization of light in the cylinder and a phenomenon in which the wavelength of interest. The interaction between these two mechanisms is called Fanoresonantie. The physicists discovered that waves at certain frequencies are scattered by resonance and non – resonantiemechanismen. By the opposite phases cancel the waves with each other on what an object ‘invisible’.
This led to an experiment in which a homogeneous object invisible was made by destructive interference or ‘verstrooiingsuitdoving’. The technique made it possible to move between visibility and invisibility to turn on the same frequency of 1.9 GHz by the water temperature change from 90 to 50 degrees Celsius.
The big difference with many other investigations of invisibility is that no use need to be of a metamateriaal. Materials with a matching refractive index already exist or can be developed.
The results could, for example, application can be found in the development of nanoantennes, in which the practical may be to “invisible” structures such as elements to use. Think of invisible rods to antennechips to separate where ordinary rods of interference by the radio waves to block. The materials were developed in such a way that they can be invisible to a specific wavelength.
Credit: ITMO University