From Athena’s cap of invisibility to H.G. Wells and Harry Potter, the notion of making oneself invisible has always tickled human fantasy. Incredibly, technological advancements over the last few years have brought these fantasies into the real world.
The latest invisible tech, called Quantum Stealth, has been developed by Hyperstealth, a Canadian camouflage design company. The material is as thin as paper, inexpensive, and requires no power source. While it doesn’t work quite as well as a magical cloak, it does a pretty good job of concealing and is certainly confusing to look at.
The material uses an approach that you might already be familiar with: lenticular lenses. If you have seen one of those pictures that appears 3D depending on how you look at it, you have seen this tech.
In a similar manner, the material can bend light in a way that means only things very close or very far away can be seen. So an object or person placed behind it at a certain distance will become invisible. The material has quite the broadband capability and is able to bend light from mid- and near-ultraviolet to the infrared. Given the lower resolution of cameras that work outside the visible light spectrum, the effect becomes a lot more pronounced and remarkable when the material is viewed through them.
The material is not affected by the colors of what it's trying to conceal but it does distort the background. So it's not a magical invisibility cloak; people will know that something is hidden behind it, they just won’t be able to discern the details of what it is.
The technology started being developed by Hyperstealth's Guy Cramer in 2010, and since then he’s been working with military organizations to get it developed. He recently filed four patents on this and related technologies and published a series of videos on how it works.
While the details are obviously under wraps, the physics is surprisingly straightforward. The principle is known as Snell’s law. Every material has a specific refractive index, a quantity related to the speed of light in that material compared to the speed of light in a vacuum.
You can see the effect easily. Get a glass of water and put a spoon in it. It will appear bent. The same effect makes pools appear shallower than they are. When light moves between two materials, the angle at which it is moving will change depending on the refractive index. So by being clever with materials it is possible to construct something that has a blindspot. And that’s where the invisibility happens.
Check out an extract from Hyperstealth's video below