Recent coatings research has produced more “invisibility cloaks” than Harry Potter ever dreamed of. Now, University of Texas researchers have developed another one, using the so-called mirage effect.
Dr. Ali Aliev, a research scientist at UT Dallas, and colleagues recently demonstrated that transparent carbon nanotube sheets, which can have the density of air and the specific strength of steel, can be used to make objects invisible.
Aliev uses thread-like carbon nanotubes and heats them rapidly until the objects beneath them effectively disappear.
|A new 'invisibility cloak' uses an effect similar to that of mirages.|
The effect is similar to the mirage that occurs on a hot highway, when distant surfaces look like shimmering puddles of water. That illusion is caused by hot air above the road, which refracts light waves coming down from the cooler air—a phenomenon technically known as photothermal deflection.
The same effect can be accomplished with a coating that uses carbon nanotubes, researchers say. A video shows how it works.
“The remarkable performance of nanotube sheets suggests possible applications as photo-deflectors and for switchable invisibility cloaks, and provides useful insights into their use as thermoacoustic projectors and sonar,” the scientists reported in an article published in the journal Nanotechnology.
“Visibility cloaking is demonstrated in a liquid.”
At present, Aliev can make only tiny sheets from a few threads, he told NBC. But other scientists are also working on the technology. UK scientists, for example, are working to develop temperature-controlled plates to attach to tanks that would make them disappear when viewed through night-vision goggles.
Aliev’s research work was supported by Office of Naval Research, NASA, the Air Force Office of Scientific Research and Robert A. Welch Foundation.
The Rush to Disappear
Reports of various types of cloaking and blackening effects using coatings have been accelerating in recently years. In 2011 alone:
• UK defense contractor BAE Systems said it was developing “electronic ink” technology that could camouflage military vehicles, rendering them essentially invisible.
• A University of Michigan research team announced that it had developed a coating that acts as a “magic black cloth.”
• NASA announced a “super-black” material that absorbs more than 99 percent of the ultraviolet, visible, infrared and far-infrared light that hits it.
• Federal authorities investigated the defacing of several Southwest Airlines 737s with a special “invisible paint” that appeared only after the plane was warmed with an auxiliary power unit.