We’re Getting Really Close to Making a Superpower Reality

Ever want to be invisible? It could happen soon in America, unless Canada beats us to it.

National Journal
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Ben Terris
Nov. 18, 2013, 6 a.m.

The greatest hy­po­thet­ic­al ques­tion of all time may be one step closer to be­ing an­swer­able. No, no one has yet in­ven­ted a horse-sized duck or a thou­sand duck-sized horses. I’m talk­ing about the greatest hy­po­thet­ic­al ques­tion: flight or in­vis­ib­il­ity?

Ex­per­i­en­cing something ap­proach­ing hu­man flight has long been pos­sible. For a price, any­one can leap out of a plane with a para­chute, and jet­packs can make up the dif­fer­ence. As for the second, more elu­sive part of the equa­tion? Re­search­ers from Texas and Toronto say they have in­ven­ted two dif­fer­ent types of in­vis­ib­il­ity cloaks. For now, these devices only make things seem to dis­ap­pear on wavelengths un­detect­able to the hu­man eye, but re­search­ers on both products say a full-scale in­vis­ib­il­ity cloak is no longer just an im­possible dream.

While the al­lure of the power of in­vis­ib­il­ity goes back at least as far as H.G. Wells’ The In­vis­ible Man — if not Greek myth­o­logy — it first be­came a sci­entif­ic real­ity in 2006. That year, re­search­ers at Duke Uni­versity had cre­ated a cloak­ing device that could make tiny, two-di­men­sion­al ob­jects ap­pear in­vis­ible to mi­crowaves.

But this cloak, and oth­ers like it, were a far cry from any­thing you’d read about in a Harry Pot­ter book or see in a Star Trek epis­ode (*re­quired ref­er­ences in any art­icle about in­vis­ib­il­ity cloaks*). One of the ma­jor prob­lems, ac­cord­ing to a new pa­per from Dr. An­drea Alú from the Uni­versity of Texas (Aus­tin), is that while it makes ob­jects in­vis­ible in one fre­quency, it ac­tu­ally makes them more vis­ible un­der an­oth­er fre­quency. An ob­ject made in­vis­ible in red light, for ex­ample, would be even more vis­ible in blue light.

But Alú says he has in­ven­ted a new type of device that fixes that prob­lem. Like the cloaks of yore, Alú’s new design uses meta-ma­ter­i­als (syn­thet­ic tex­tiles with prop­er­ties not found in nature) that can bend light around an ob­ject and make it look like it’s not there. But, by adding an elec­tron­ic source like a bat­ter to the cloak (mak­ing the cloak “act­ive” as op­posed to “pass­ive”), Alú says he can make ob­jects trans­par­ent at “all angles and over all broad band­widths.”

Nat­ur­ally, a lot of the fund­ing for this re­search comes from the De­fense De­part­ment: Want an air­plane or a tank to be in­vis­ible to radar? This is the type of device for you. But it’s not just the mil­it­ary that is in­ter­ested. Alú says a good chunk of fund­ing comes from wire­less pro­viders. Be­cause if a build­ing is in the way of your wire­less sig­nal, mak­ing it in­vis­ible might be a bet­ter al­tern­at­ive than knock­ing it down.

Alú says he ex­pects to have a ver­sion of this device built with­in the next couple of years.

Why the hurry? Maybe it’s so we can get one be­fore Canada does. Re­search­ers at the Uni­versity of Toronto seem to be neck and neck with the U.S.

In a re­cent pa­per pub­lished in the Phys­ic­al Re­view X, Toronto pro­fess­or George Eleftheri­ades and his stu­dent Mi­chael Selvanay­agam de­scribe a device made up of a series of an­ten­nae that can ra­di­ate light and ra­dio waves away from the ob­ject it sur­rounds. But these re­search­ers have done more than just write about such a device; they’ve jury-rigged one up us­ing Styro­foam, mask­ing tape, and 12 an­ten­nae. It cost un­der $2,000 and has been nick­named “the act­ive cloak ma­chine.”

It es­sen­tially works like this: Say you shine a beam of ra­dio waves at an ob­ject. When the waves hit the ob­ject, they will bounce back. But if you sur­round the ob­ject with an­ten­nae that bounce back the op­pos­ite ra­dio waves, it will seem as if the ob­ject is not there.

When asked who might be in­ter­ested in such a device, Eleftheri­ades stuttered a bit.

“The mil­it­ary is the most ob­vi­ous,” he said. “We have been ap­proached”¦. I shouldn’t say too much about that.”

As for wheth­er this could ever be ap­plied to mak­ing someone or something in­vis­ible to the hu­man eye, Eleftheri­ades says there’s no reas­on it couldn’t scale up, it would just need the right kind of an­tenna (ones that don’t yet ex­ist).

So, what do re­search­ers have to say about the age-old ques­tion of which would be cool­er, flight or in­vis­ib­il­ity?

“I think be­com­ing in­vis­ible,” said Eleftheri­ades. “Be­cause this ex­per­i­ence, no hu­man has had it be­fore. Maybe we can­not fly on our own, but we know how it feels to fly.”

And des­pite their friendly com­pet­i­tion on the sub­ject, Alú can agree with his col­league on this.

“I would choose in­vis­ib­il­ity,” Alú said. “Fly­ing is easi­er to achieve in oth­er ways, and I know ex­actly how hard it is to achieve in­vis­ib­il­ity.


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