A team of international physicists has developed homogenous cylindrical objects absolutely invisible in the microwave range.

Scientists at ITMO University, Ioffe Institute and Australian National University achieved this by making use of a homogenous object and no additional coating layers were added. Method used by physicists was based on a new understanding of electromagnetic wave scattering. The findings of the study have been published in Scientific Reports.

In the study, the physicists examined light scattering from a glass cylinder filled with water. The experiment shows a two-dimensional analog of a classical problem of scattering from a homogeneous sphere (Mie scattering). However, this was a totally different case as it includes unusual physics.

The scientists used ordinary water for the experiment; the water whose refractive index can be controlled by changing temperature.

According to Mikhail Rybin, first author of the paper and senior researcher at the Metamaterials Laboratory in ITMO University, "Our theoretical calculations were successfully tested in microwave experiments. What matters is that the invisibility idea we implemented in our work can be applied to other electromagnetic wave ranges, including to the visible range. Materials with corresponding refractive index are either long known".

Engineering is also seen from a different perspective with the discovery of invisibility phenomenon in a homogenous object, which is not an object covered with additional coating layers. The discovery could lead to further development of nanoantennas, in which invisible structural elements could help lessen disturbances as it is much easier to create a homogeneous cylinder. For example, invisible rods could be employed as supports for a little antenna complex linking two optical chips.