Virtually everything emits heat waves: cars, electrical appliances, communication lines, human bodies and so on. And to fix this long ago there are thermal imagers. But some objects would be nice to hide from the “gaze” of these devices. And, according to the journal Advanced Engineering Materials, a group of scientists from the University of Wisconsin in Madison succeeded in creating a material that makes objects invisible in the infrared range.
A team of scientists led by Professor Hongzhun Jiang is behind the invention. The new material is very similar in appearance to metal. Its sheets with a thickness of less than 1 millimeter absorb about 94% of infrared radiation with a wavelength of 2.5 to 15.5 micrometers. The invention works most efficiently in the middle and in the far infrared ranges, in which, for example, the human body actively transfers heat.
In order to achieve the above-described effect, scientists used the recently popular metamaterials, namely, “black silicon.” It is a smooth material that “looks under the microscope” like a dense heap of small bars. But a group of scientists improved the material, creating higher bars and adding silver nanoparticles to them. Due to this structure, the material can absorb radiation in the infrared range.
It is not difficult to guess that such an invention will perfectly suit the military as a means of masking soldiers and military equipment. However, experts during the development came up with a small bonus. In the metamaterial small infra-red radiators were built in. They are controlled remotely and can create an “illusion” of the object, confusing infrared sensors. For example, a tank covered with a metamaterial sheet will look like a boiler or something more exotic.