The Next Big Thing in Stealth Technology? A Cloaking Device
There are quite a few futuristic technologies depicted in classic science-fiction movies and TV shows that we think are completely plausible and we'd totally love to have...even though we have no idea how the science behind them would work. The lightsaber (which is close to happening) is a big one. Another would definitely be the hoverboard from Back to The Future 2. And of course, there's the concept of a cloaking device from Star Trek. Just think how amazing it would be for a fighter pilot to simply flip a switch and BOOM no one would know he and his plane were even there. Now, thanks to researchers at the Cockrell School of Engineering School in Austin Texas, cloaking might soon go from the future to the present.
From Sci-Fi to Science
Science fiction concepts like lightsabers, hoverboards, and cloaking devices often inspire real-world research, even when the science isn’t fully solved yet.
Andrea Alu, an associate professor at the engineering school, has developed a design for a cloaking device that uses an external power source. By adding a battery, the device would be able to cloak itself in conditions outside of a lab. This is different than how previous cloaking technology has worked in the past.
It seems that "passive cloaking" [a term used to describe older cloaking tech] works by scattering light that bounces off an object, but as science site Red Orbit explains: "When the cloak’s scattered fields and the object interfere, they cancel each other out, resulting in the object being transparent to radio-wave detectors. In the future, cloaks could be designed to let the object be more difficult to see with the naked eye, but currently they only work on radio waves."
Passive Cloaking Has Limits
Current cloaking technologies only work under narrow conditions and are typically limited to specific radio-wave frequencies, not visible light.
"Many cloaking designs are good at suppressing the visibility under certain conditions, but they are inherently limited to work for specific colors of light or specific frequencies of operation," Alu explained in the press release for his theory.
“Many cloaking designs are good at suppressing the visibility under certain conditions, but they are inherently limited to work for specific colors of light or specific frequencies of operation,”
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Alu lays out his plan in his paper titled "Broadening the Cloaking Bandwidth with Non-Foster Metasurfaces." The "Foster" part is regarding Foster's Theorem, which states that radio waves amplify when they're projected. The more radio waves generated, the less "invisible" a cloaking device is. Alu says his project has found a way around Foster's Theorem.
Breaking a Physics Rule
By using powered amplifiers, Alu’s design sidesteps Foster’s Theorem, allowing cloaking performance to improve across a wider range of frequencies.
"In our case, by introducing these suitable amplifiers along the cloaking surface, we can break the fundamental limits of passive cloaks and realize a ‘non-Foster’ surface reactance that decreases, rather than increases, with frequency, significantly broadening the bandwidth of operation," Alu is quoted saying.
Keep in mind that Alu's idea won't mean you'll be able to buy your invisibility cloak, a la Harry Potter. Not yet at least. What he's working on would make planes more undetectable to modern radar tracking. Picture a Stealth Bomber on steroids (which is why Alu's research is funded by the Air Force of Department of Defense). But don't worry, if he's right Alu's idea could mean that someday the cloaking device that allows us to be in rooms completely undetected, and then — then! — we will have our revenge! Uh, sorry. Got carried away there. Don't ask.
[Image via Flickr - D. Miller]
