Researchers Create Ultra-Thin Invisibility Coat, Thinner Than Anything Harry Potter Owns
The invisibility cloak has long been featured in sci-fi and fantasy novels like "Harry Potter", tantalizing our imaginations with all its wonderful possibilities, and now a research team has created one that is micrometers thick.
Researchers at The University of Texas at Austin have developed a cloak that is just micrometers thick and can hide three-dimensional objects from microwaves in their natural environment, in all directions and from all of the observers' positions. The study was published on Tuesday in the Institute of Physics and German Physical Society's New Journal of Physics. The ultra-thin coat is made of a new kind of material called a metascreen, created from strips of copper tape attached to a flexible polycarbonate film.
The copper strips are only 66 micrometers (66 millionths of a meter) thick, while the polycarbonate film is 100 micrometers thick, and the two are combined in a diagonal fishnet pattern.
The researchers used the cloak to shield an 18 cm tall cylindrical rod from microwaves.
"In principle this technique may be extended to visible frequencies; in fact metasurfaces are easier to realize than metamaterials in optics. However, the object size that can be efficiently cloaked with this method scales with the wavelength, so when applied to optical frequencies we may be able to efficiently stop the scattering of only micrometer-sized objects," the research paper claims.
The researchers reported that invisibility effect was present over a moderately broad bandwidth, with optimal performance at a wavelength of 3.6 gigahertz. The same technique could be used to produce invisibility in different wavelengths.
The cloak works optimally at 3.7GHz, researchers say, but it could be applied to visible frequencies.
"In principle, this technique could also be used to cloak light," Alu said in a news release. "In fact, metascreens are easier to realize at visible frequencies than bulk metamaterials, and this concept could put us closer to a practical realization. However, the size of the objects that can be efficiently cloaked with this method scales with the wavelength of operation, so when applied to optical frequencies, we may be able to efficiently stop the scattering of micrometer-sized objects."