NSU Helps Move “Invisibility Cloaking” Forward

Imagine a friend tells you that they just painted their kitchen “blue.” You might ask if it’s Navy Blue, Sky Blue or Turquoise. But if they told you they painted a wall “black,” you wouldn’t have any such questions. There’s only one shade of black, right? Wrong. At least if work being conducted by Mikhail Noginov, Ph.D., at the NSU Center for Materials Research continues to evolve. Noginov and his colleagues, including Professor Evgeni E. Narimanov of Purdue University, who has proposed the concept, are developing materials that are best described as “blacker than black.”

These new, high-tech substances are the next step in what Noginov calls the development of material science reaching as far back as the Stone Age, the Bronze Age, and even to the more recent rise of Silicon Valley. Termed “Metamaterials,” these materials work by altering light in ways heretofore impossible in any naturally occurring substance.

The science is complex, with work taking place at the ultra-small nanoparticle level. In the simplest terms, the Metamaterial bends incoming light waves in unnatural directions, either changing their final appearance or preventing them from being reflected all together.

One example that illustrates this concept is placing a straw into a glass of water. In a “normal” material, the straw will appear to bend slightly due to refraction but still continues in the same general direction. However, in a negative index Metamaterial, the straw would appear to bend almost backwards, its reactions altered by the Metamaterial’s specially aligned arrangements of nanoparticles.

Another, albeit simplistic, example is the image of water entering a sponge. Most of the water is held within the sponge’s surface, with only a small percentage escaping. In a Metamaterial such as that under development at NSU, light replaces water, and theoretically, all of the light that enters the material is scattered inside, with little or no light escaping.

Noginov’s research, funded by both the Department of Defense and the National Science Foundation, could have implications for civilian and military uses. Among these are enhancements in the field of optics, greatly enhancing the resolution of optical microscopes and other tools.

On the military side, the potential uses might seem more like science fiction than fact. Through the application of Metamaterial light distortion, it may one day be possible to produce a complete “invisibility cloak” around Army tanks or Navy submarines. By altering how light passes around and through the material, researchers at NSU and other centers hope to effectively delete an object from an observer’s view, rendering it functionally invisible.

And it may not be just light that can be altered. “If we can translate the current metamaterial technology to RADAR wavelengths,” says Noginov, “the next step could be enhancements to our military stealth technology.”

Noginov, who has been at NSU since 1997, leads a team of doctoral, master’s and undergraduate students working in partnership with researchers at Cornell and Purdue Universities. “The Center for Materials Research is a fairly small center in the area of Materials,” says Noginov of the NSU efforts, “but we have a number of people here at the top of their fields. Just like our materials, our mass may be small, but our quality is high.”

Heath E. Covey is a professional writer and communicator working in Hampton Roads.

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