New Material Could Make Objects Invisible

News
By last updated
Photo (Image credit: U.S. Air Force)

Scientists have taken another step toward the goal of rendering objects invisible using high-tech cloaks that redirect light.

Researchers for the first time demonstrated that a new material can bend visible light the wrong way in three dimensional tests. It builds on research that cloaks objects in the microwave wavelength.

The metamaterial, as it is called, produces what's known as negative refraction of visible light. That means light is made to travel in the opposite direction from how it normally should bend when passing through a material. A common example is how a pencil will appear to bend upward when half-submerged in a glass of water. In the new work, researchers make the light appear to bend the other way.

Metamaterials are artificially engineered structures that have "extraordinary optical properties that do not exist in nature," the researchers write in Science. "They can alter the propagation of electromagnetic waves, resulting in negative refraction, subwavelength imaging and cloaking."

Visible light is just one type of electromagnetic radiation, a spectrum that includes everything from radio waves to X-rays and more.

Until now, the effectiveness of the cloaking has been demonstrated only in thin, two-dimensional materials.

Now at a National Science Foundation lab at the University of California, Berkeley, Jason Valentine, Jie Yao, Xiang Zhang and others have create a multilayered, "fishnet structure" that "unambiguously exhibits negative refractive index," they write.

"This straightforward and elegant demonstration enhances our ability to mould and harness light at will," according to a statement from the journal Nature.

Other research has looked into using plasmons — tiny electronic excitations on the surfaces of some metals — to cancel out the visible light or other radiation coming from an object and effectively cloak it.

Sci-fi fans know that cloaking technology made Romulan spaceships disappear in Star Trek. Among the real applications pondered for the future of real-world cloaking technology: stealth military devices and new medical techniques.

TOPICS
Robert Roy Britt
Robert Roy Britt

Robert is an independent health and science journalist and writer based in Phoenix, Arizona. He is a former editor-in-chief of Live Science with over 20 years of experience as a reporter and editor. He has worked on websites such as Space.com and Tom's Guide, and is a contributor on Medium, covering how we age and how to optimize the mind and body through time. He has a journalism degree from Humboldt State University in California.