Researchers at UC Berkeley are a step closer to the fabled invisibility cloak. The new study published in the journal Science details a new super-thin metamaterial that scatters light, effectively obscuring the object beneath the cloak. This cloak has several properties that were missing from previous invisibility materials, and it’s got other researchers very interested.
The cloak described in the paper is small, just 1.3 square centimeters. However, it’s a good proof of concept for this new material. Past invisibility materials have relied on complicated means of redirecting light around the object they were hiding. This was effective technically, but that meant the materials were thick and bulky.
The new cloak developed by the Berkeley team is only 80 nanometers thick — so thin it could be integrated into clothing.
The researchers made the leap from bulky to thin by giving up on redirecting light and are instead scattering it using physical structures. The metamaterial is covered in tiny nanoantennas made of gold blocks. The varying size of the blocks counteracts the distortion of light after it hits the cloak. It essentially makes it behave as if it had bounced off a completely smooth surface, thus hiding the contours and detail of the object beneath the cloak. It could theoretically also be used to perform the opposite — turning a 2D image into 3D, making it ideal for use holographic displays and virtual reality.
Aside from only working on the small scale, the metamaterial can only scatter a narrow wavelength of light. Specifically 730nm, which is nearly in the infrared. The effective range would need to be expanded to cover the entire visual spectrum before it would be useful in practice.