Invisibility Cloaks Could Change the Face of Military Operations

Scientists in California have developed an invisibility-cloak style material that could be used in military operations, which could allow weaponry and even personnel to go undetected.

U.S. military newspaper Army Times reported that the team from the University of California, San Diego (UCSD) have tested the first effective dielectric metasurface material—an ultra-thin, non-metallic material with properties that means it can manipulate electromagnetic waves, including light and radio waves, so that the object is no longer detectable. The researchers tested the material with microwaves, but believe it could also be effective at other wavelengths.

Boubacar Kanté, the author of a study reporting the findings that was originally published in the journal Progress in Electromagnetics Research, told Army Times that he had been in contact with the U.S. Department of Defense (DoD) about the project and was submitting a proposal to them later this month. A DoD spokesman told Newsweek that the Pentagon could not confirm or deny that this was the case.

The new material consists of a layer of polytetrafluoroetheylene (commonly known by the brand name Teflon) with multiple, small ceramic cylinders embedded in it. Kanté says the material is unique in that it works at one-tenth of the wavelength trying to be avoided. In other words, in order to make an object undetectable to a 3 cm (30 mm) wavelength—the typical wavelength used by missile guidance and marine radar systems—a 3 mm coat of the material is required. Previous stealth-enhancing materials required much thicker coats in order to be effective.

Currently, the material developed by the UCSD team only functions with light hitting it within a six-degree range of angles—meaning that objects coated with it only go undetected when light hits them at a certain angle. Kanté said they were working to expand the range.

Kayla Matola, a research analyst for the Homeland Defense & Security Information Analysis Center (HDIAC), which is sponsored by the DoD to work on applying academic research to military purposes, told Army Times that the material is "basically what the military's looking for" and estimated it could be utilized within five to 10 years. She added it could "provide the military with air superiority," suggesting it could be used for stealth fighter jets or in unmanned aerial vehicles, also known as drones.

However, Justin Bronk, a research analyst in military sciences at U.K. defence think tank RUSI, told Newsweek that the main applications of such technologies are likely to be in land-based military systems, such as mounted weapons and snipers trying to remain concealed.

He says the chief challenge in creating something which is truly invisible is dealing with the various wavelengths of different forms of electromagnetic radiation. The electromagnetic spectrum includes radio waves, which have a wavelength of more than 1 mm, as well infrared and visible light waves, which can have wavelengths as short as 750 nanometers (nm) and 400 nm respectively.

"There's always a trade-off in terms of which spectrum you are trying to reduce your detectability in," says Bronk. For example, one of the properties of radar-absorbent materials—which are used in fighter jets to reduce their detection on radar systems—is that absorbed radar waves are converted into heat. So while their radar detectability is reduced, their infrared signature is increased. "The perfect invisibility coat in all spectra is something far, far beyond material science at the moment," says Bronk.

Even if such technologies do become a reality, they are likely to remain a specialist domain for the foreseeable future, according to Bronk. "I expect we'd see it first in the toolkit of special operators or exotic jobs like that, rather than something that your individual soldier or battle tank will tend to mount."