The invisibility cloak is not just a J.K. Rowling thing anymore – sort of. Scientists have been studying and perfecting the concept for years.
Now, electrical engineers at UC San Diego say they have developed a slimmer design for a cloaking device.
“Previous cloaking studies needed many layers of materials to hide an object, the cloak ended up being much thicker than the size of the object being covered,” said Li-Yi Hsu, electrical engineering Ph.D. student at UC San Diego and the first author of the study. “In this study, we show that we can use a thin single-layer sheet for cloaking.”
The theory behind invisibility is that it can be achieved using man-made materials that bend electromagnetic waves, like visible light, around objects to create the illusion of a flat surface.
“Invisibility may seem like magic at first, but its underlying concepts are familiar to everyone. All it requires is a clever manipulation of our perception,” said Boubacar Kanté, a professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering and the senior author of the study. “Full invisibility still seems beyond reach today, but it might become a reality in the near future thanks to recent progress in cloaking devices.”
According to UCSD existing cloaking devices reflect light at a lower intensity than what hits its surface, something their design sidesteps by not using metal particles, which absorb light. Their design uses a proprietary ceramic and Teflon.
“Imagine if you saw a sharp drop in brightness around the hidden object, it would be an obvious telltale,” said Kanté. “[This cloak] won’t lose any intensity of the light that it reflects.”
Researchers used design software with electromagnetic simulation to design the cloak, and modeled it as a thin matrix of Teflon, with different heights depending on its position in the cloak.
“By changing the height of each dielectric particle, we were able to control the reflection of light at each point on the cloak,” explained Hsu. “Our computer simulations show how our cloaking device would behave in reality. We were able to demonstrate that a thin cloak designed with cylinder-shaped dielectric particles can help us significantly reduce the object’s shadow.”
Kante says with this new technology scientists could change the way light waves are being reflected which could help solar power. They also expect it to have implications for optics, interior design and art.