Invisibility cloaks have been around for a while, albeit not in the way you see in Harry Potter (yet). Devices made out of metamaterials, a type of engineered material designed to distort perception, are able to interact with various types of electromagnetic radiation in a way that natural materials cannot. Though prototypes of invisibility cloaks have typically had to have many layers, ending up much thicker than the objects they are attempting to hide. Another key flaw of existing cloaks is that they are ‘lossy’ which means that the metal components don’t reflect light as intensely where the covered object is, giving a conspicuously darker appearance to that area. Now, an engineering team in California says they have been able to create a thinner, ‘lossless’ and so more truly ‘invisible’ cloak.
The electrical engineers at University of California, San Diego have crafted a cloak that can cover an object atop a flat surface and to observers, it will appear completely flat. Their thin, single layer sheet of Teflon containing ceramics is actually able to make it seem like it isn't hiding anything. They eliminated the obvious change in brightness by using dielectrics—nonconductive materials that don’t absorb light. They were actually able to control reflection of light at any point by modifying the height of the ceramics in the Teflon.
More Than Invisibility
“Doing whatever we want with light waves is really exciting. Using this technology, we can do more than make things invisible. We can change the way light waves are being reflected at will,” says Boubacar Kanté, senior author of the study and a professor in the Department of Electrical and Computer Engineering at the UCSD Jacobs School of Engineering. Being able to change reflection of light is a great step towards changing light perception enough to make things totally invisible. Kanté claims complete invisibility might be a very real thing we can achieve in the near future and also highlights the new technology’s immediate applications for other industries. It will be indispensable for concentrating solar energy and speeding up signals in optical communications.