Wizards beware: Microscopic 'invisibility cloak' developed by US researchers
The cloak was produced using microscopic nanoantennas, measuring at 80 nanometers thick, which were then wrapped around a three-dimensional object, one-thousandth of an inch in size, according to researchers at the US Department of Energy's Lawrence Berkeley National Laboratory and the University of California, Berkeley.
"This is the first time a 3D object of arbitrary shape has been cloaked from visible light," said lead author Xiang Zhang, director of Berkeley Lab's Materials Sciences Division, according to AFP.
"Our ultra-thin cloak now looks like a coat. It is easy to design and implement, and is potentially scalable for hiding macroscopic objects."
Light with a wavelength of 730 nanometers was directed on the object, reflecting back almost flawlessly, they reported. Light bounced off the object without revealing its location, as if there was a flat mirror in its place, the researchers said.
"The surface of the skin cloak was meta-engineered to reroute reflected light waves so that the object was rendered invisible to optical detection when the cloak is activated," according to the study, published Thursday in the journal Science.
You don't need to be a physicist to love the invisibility cloak @sciencemagazine cover— Valda Vinson (@ValdaVinson) September 17, 2015
"Tuned" to match any background, the cloak gives the illusion of invisibility, as the gold nanoantennas controlled any scattered light, the researchers said, rendering the object invisible.
Yet the nanoantennas had to be engineered to match the object's surface texture with perfection. Thus, the object would not be able to move and retain invisibility.
The cloak also cannot mask any shadows cast by the object, according to Zeno Gaburro, a physicist at the University of Trento who wrote about the cloak in an accompanying article about the concept in Science.
"The face that is dark does not see the light, so there's no way you can correct for (the shadow) with this technique," Gaburro said.
Zhang told LiveScience that the next step is to produce the cloak at industrial scales, adjusting the nanoantennas to varying wavelengths of light.
"I don't see any roadblocks," he told AFP.
Let's get this straight: That invisibility cloak is waaaay more Predator than Harry Potter. http://t.co/Iitj0W1Mup— WIRED Science (@WIREDScience) September 18, 2015
While "invisibility cloaks" are nowadays most closely associated with the Harry Potter series, Wired magazine wrote Thursday that Zhang's research comes closer to another pop-culture phenomenon, the Predator film series starring Arnold Schwarzenegger based around an extraterrestrial that hunts humans on Earth.
"It’s another metamaterial-based design that distorts light waves around an object, making it appear as if the light is bouncing off a flat surface," wrote Wired's Katie M. Palmer of the new research.
"That general concept is exactly how the Predator’s cloaking device is supposed to work," Palmer added later. "The [Predator alien's name] Yautja’s advanced technology similarly redirects light—whether it transmits or reflects the waves is unclear—in a way that allows people to see through their bodies. Whereas Harry’s cloak is powered by…magic. [Potter author J.K.] Rowling wasn’t much for magical explanations, so all readers know about the cloak’s tech is that it somehow obscures visible light waves (and not, to hilarious effect, sound waves). If Harry dove into the concept a bit further, a la Harry Potter and the Methods of Rationality, he might have actually stumbled on a more logical, metamaterials-driven explanation for his hand-me-down’s behavior. But there’s no way for readers to ever know."
Give me Harry Potter, or give me death. No, seriously, give me death, I want an invisibility cloak.— emrys (@xAccioLovex) September 12, 2015