Professor uses nanostructures to create cloaking device

This model shows how light reflects off the device. Image: Penn State

Cloaking devices have had a major role in many science fiction narratives, but Xingjie Ni, an assistant professor of electrical engineering at Penn State, is working to make them a reality.

Ni joined the School of Electrical Engineering and Computer Science in August 2015, and he is already making headlines for his research.

While scientists have been working on creating this stealth technology for years, those who have come close have created bulky devices that can only hide very small objects. Using a metasurface, an artificially tailored surface consisting of nanostructures, Ni and his team created a “skin” cloak of very thin matter that can conform to the shape of an object and conceal it from detection with visible light. This technology will eventually be able to conceal bigger objects, including people.

“The principle is that the cloak completely restores both the wavefront and the phase of the scattered light from the object, and makes it as if it were reflected from a flat surface,” said Ni. “So the arbitrarily shaped 3-D object is hidden.”

We see an object because our eyes receive the object information by the light scatters off it. Once light reaches the eyes, the brain interprets the appearance, shape and location of whatever we are looking at. The device created by Ni’s team manipulates the light using tiny brick-like blocks of gold antennas that change the way the light scatters and makes it appear as it were a flat surface.

Ni’s research was published last month as a cover story  in Science. Since then, articles about his work have appeared on news sites such as ABCNBCBBCFox News and the Washington Post. A YouTube video showing a test of the cloak has been viewed more than 308,000 times.

While Ni’s work on the cloak began at the University of California, Berkeley, where he was a postdoctoral fellow, he will continue his research on the metamaterial with graduate students at Penn State.