A team of scientists has created a material that’s enough to confuse fellow researchers and the Predator alike: a substance that looks cold when viewed using infrared light, even when it’s getting hotter.
Typically, when objects get hotter, they radiate more infrared light — which can be detected using infrared cameras like those found in military goggles. Now, scientists are working out how to design materials that don’t follow that rule.
That’s possible if you can find a way of making them interact with light or electricity differently as their temperature changed. The Harvard researchers realised that vanadium dioxide switched abruptly from being an electrical insulator to a conductor at about 70C — and thought they might be able to use it to their advantage. So, they coated a wafer of sapphire with a 150-nanometre-thick layer of vanadium dioxide and set to playing.
Heating their disc and looking at it through infrared cameras revealed that it emitted more and more infrared light until it reached 74C — but then, with more heating, it appeared to spew out less. In fact, the readout of the infrared camera pegged its temperature at around 50C when it was actually at 90C.
The research, published in Physical Review X, could help provide camouflage against heat-sensing cameras. Essentially, the material is capable of concealing its true temperature, which could be used to trick thermal sensors. Just a shame that it means the Predator might not have quite such an easy ride anymore. [Physical Review X via Science News]