You Can Make Yourself a Cloaking Device For Only \$150 | The Mary Sue

### Shields Up: Now You Can Make Yourself a Cloaking Device For Only \$150

#### "Think of all the shoulderpads we can buy with the savings!"

Sure, it’s probably not going to be as good for protection as a Romulan Warbird or a Deathly Hallow, but if you follow the exact process that students and professors from the University of Rochester used, you’ll have yourself one of the first devices capable of “three-dimensional, continuously multidirectional cloaking.” Sweet.

The brainchild of Professor John Howell and graduate student Joseph Choi (whom the above quote is from), the “Rochester Cloak” isn’t your average high-tech cloaking device; rather than using exotic materials to bend light around an object as if it were not there, it uses four ordinary consumer-grade lenses to achieve the same effect.

See it in action:

As Choi notes, it only works for small angles and isn’t capable of cloaking the exact center of its field, but it also won’t distort the background behind the object or give the object away when you change positions, and it can be scaled up as long as you have the lenses for it. PhysOrg explains:

In order to both cloak an object and leave the background undisturbed, the researchers determined the lens type and power needed, as well as the precise distance to separate the four lenses. To test their device, they placed the cloaked object in front of a grid background. As they looked through the lenses and changed their viewing angle by moving from side to side, the grid shifted accordingly as if the cloaking device was not there. There was no discontinuity in the grid lines behind the cloaked object, compared to the background, and the grid sizes (magnification) matched.

But don’t take their word for it. If you want to make one yourself, all you need are the same kinds of lenses Choi and Howell used. (Uproxx calculates that it’ll cost you \$150):

Purchase 2 sets of 2 lenses with different focal lengths f1 and f2 (4 lenses total, 2 with f1 focal length, and 2 with f2 focal length)
Separate the first 2 lenses by the sum of their focal lengths (So f1 lens is the first lens, f2 is the 2nd lens, and they are separated by t1= f1+ f2).
Do the same in Step 2 for the other two lenses.
Separate the two sets by t2=2 f2 (f1+ f2) / (f1— f2) apart, so that the two f2 lenses are t2 apart.

The cloaking device is an incredibly popular concept in science fiction and fantasy, including Star Trek, Harry PotterPredator, and countless other franchises—but John Howell believes that our scientific fascination with these devices runs much deeper than that. “I think people are really excited by the prospect of just being invisible,” he said.

(via Uproxx)