Chameleons, unlike bowties, are cool. The chameleon is most famous for its ability to blend with its surroundings (I’m just as impressed with the acrobatic tongue), something we’d often like to do ourselves. Doing something similar with heat would be exciting. Imagine a camouflage suit that blended in with its background in both the visible and the infrared.
Three researchers suggest they’ve done exactly that in a recent paper on a thermal cloaking demonstration. Unfortunately, their cloak doesn’t so much blend with the surroundings as become completely transparent. This is still remarkable, and, at least when cloaking in two dimensions, it’s surprisingly simple to make.
Hiding in plain sight
Before we get to how the cloak works, let me take you through what the thermal chameleon is trying to hide. Let’s imagine that I have a long cylinder. At one end, I heat the cylinder to 50°; and at the other end, I cool it to 10°. If I measure the temperature along the length of the cylinder, it will decrease steadily between the hot end and the cold end.