This invisibility cloak might not make you invisible for human eyes, but it can surely hide you from infrared eyes
To provide the invisibility from infrared cameras, Scientists from the University of Wisconsin-Madison have come up with a new cloaking material that makes people and objects invisible to the infrared cameras.
Working of invisibility cloak
Warm objects like human bodies or tank engines emit heat as infrared light, the infrared cameras are the heat-sensing eyes that use these emitted radiations to find their targets even in the dead of night or through heavy fog. They are used in drones for surveillance, especially at borders.
Hiding from such detectors has now become easier as researchers have made a sheet that can absorb approximately 94 per cent of the infrared light it encounters. Due to trapping of so much light, the warm objects beneath the cloaking material become almost invisible to infrared detectors.
The sheet is less than one-millimetre thick and material can strongly absorb light in mid and long-wavelength infrared range, the type of light emitted by objects at approximately human body temperature.
To trap infrared light, they have used black silicon that is commonly incorporated into solar cells. Black silicon absorbs light because it consists of millions of microscopic needles (called nanowires), pointing upward like a densely-packed forest.
The incoming light reflects back and forth between the vertical spires, bouncing around within the material instead of escaping. Although black silicon has long been known to absorb visible light, its potential to trap was not explored yet. The researchers boosted its absorptive properties by tweaking the method through which they created their material.
Researchers have also created a high-tech disguise for tricking infrared cameras by incorporating electronics heating elements into the sheet. They explained that infrared detectors can be deceived by presenting a false heat signature, for example, a tank can be made to look like simple highway guardrail
In addition to all these, the researcher’s black silicon also has a flexible backing interspersed with small air channels, which prevent the sheet from heating up too quickly due to absorption of infrared light.