Flexible, Ultra-thin Invisibility Cloak Now Exists: Harry Potter Fans Rejoice
Here's some news for all you Harry Potter fans out there. An invisibility cloak now exists--though it currently only works in microwave light rather than visible light.
Previous attempts at creating an invisibility cloak have resulted in large, desk-mounted constructions that are far from the light, airy cloak that features in the famed Harry Potter films. Yet the newest creation, made by University of Texas researchers, is a mere 166 micrometers thick; it's one of the thinnest ever constructed.
Most invisibility cloaks are created out of metameterials, which are materials with properties that can't be found in nature. In the case of cloaking, the materials usually have a negative refractive index, which allows for the creation of superlenses that bend light beyond the diffraction limit. This essentially means that the cloaks can bend light in such a way as to make the covered object invisible.
The newest cloak, named a "metascreen," doesn't use metamaterials. Instead, it uses a very thin sheet of copper that's attached to a sheet of flexible polycarbonate. This cloak is then attached to an object (a 7-inch-long cylinder, in this case), so that the cloak perfectly conforms to its shape. The copper and the polycarbonate create a diagonal fishnet pattern.
"When the scattered fields from the cloak and the object interfere, they cancel each other out and the overall effect is transparency and invisibility at all angles of observation," said Andrea Alu, one of the researchers, in an interview with CBS News.
In tests, the researchers were able to successfully hide the cylinder from view in microwave light. Since most radar installations use microwaves, this could have major implications for cloaking aircraft and other vessels.
Yet the invisibility cloak may not just be applicable to microwaves. It could potentially be used to hide objects in the visible range of light, as well. That said, it may only work for tiny objects at first.
"In fact, metascreens are easier to realize at visible frequencies than bulk materials, and this concept could put us closer to a practical realization," said Alu in an interview with CBS News.
The findings are published in the New Journal of Physics.