Invisibility cloaks are a staple in science fiction and fantasy, with mentions of them in folklore dating back nearly a millennium. These days, invisibility cloaks are getting closer and closer to becoming reality not thanks to not magic, but to science.
Advances in cloaking technology have been limited by the need for layer upon layer of material, which made them impractically thick. Scientists found that a single layer of teflon studded with tiny bits of ceramic not only solves this problem, but also eliminates the issue of losing brightness in the area hidden by the cloak, researchers report in a paper published in the journal Progress In Electromagnetics Research.
"Doing whatever we want with light waves is really exciting," Boubacar Kanté of the UC San Diego Jacobs School of Engineering said in a statement. "Using this technology, we can do more than make things invisible. We can change the way light waves are being reflected at will and ultimately focus a large area of sunlight onto a solar power tower, like what a solar concentrator does. We also expect this technology to have applications in optics, interior design and art."
The researchers used a "carpet" cloak design. As the name suggests, this type of cloaking device makes objects on a flat surface disappear beneath it. To do this, it mimics the way light would reflect off of the flat surface if the object were not there. What we see is based entirely on the reflection of light, so by effectively canceling out the reflections of light from the object, the cloak makes the object difficult or impossible to detect with the human eye.
Previous designs for cloaking devices have done a less-then-perfect job of this because they are "lossy," meaning that they absorb some light that should be reflected. In many cloaking devices, this is due to the use of metal particles, but the new design avoids this issue by using teflon and ceramic, neither of which contain metal particles.
"Imagine if you saw a sharp drop in brightness around the hidden object, it would be an obvious telltale. This is what happens when you use a lossy cloaking device," Kanté said in a statement. "What we have achieved in this study is a 'lossless' cloak. It won't lose any intensity of the light that it reflects.
Since these new cloaking devices are limited to use on flat surfaces, you can't exactly just wrap yourself in this new material and become invisible. However, you might still want to start rethinking your answer to the classic question of whether you'd rather have the superpower of flight or invisibility as scientists continue to craft better cloaking devices.
Photo: J E Theriot | Flickr