No Metamaterial Coatings Required for This Invisible Object

Imagine creating an object that's completely invisible in the microwave range. Scientists have constructed a homogenous cylindrical object that's invisible without the use of any additional coating layers.

In this latest study, the researchers studied light scattering from a glass cylinder filled with water. Such an experiment represents a two-dimensional analog of a classical problem of scattering from a homogeneous sphere (Mie scattering). However, this classical problem contains unusual physics that manifest themselves when materials with high values of refractive index are involved. In this particular study, the researchers used water, which has a refractive index that can be regulated by changing temperature.

A high refractive index is associated with two scattering mechanisms called resonant scattering and non-resonant scattering. The interaction between these two is referred to as Fano resonances.

"Our theoretical calculations were successfully tested in microwave experiments," said Mikhail Rybin, first author of the new study, in a news release. "What matters is that the invisibility idea we implemented in our work can be applied to other electromagnetic wave rangers, including to the visible range. Materials with corresponding refractive index are either long known or can be developed at will."

The ability to have invisibility in a homogenous object and not one covered with additional coating layers is important from an engineering point of view. This is because it's much easier to create a homogenous cylinder.

The findings could be used to create invisible rods that act as supports for a miniature antenna complex, and other applications.

The findings are published in the journal Scientific Reports.

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).