Invisibility has long been a dream of science fiction and fantasy, and scientists have been working on creating a cloaking device for some time. But what researchers at the University of Rochester have done is create such a system using off-the-shelf parts (mainly consumer-grade lenses) and math, which is free if you’re not counting the price of an advanced degree.
Professor John Howell and graduate student Joseph Choi wanted to build a device that didn’t distort the background or give away the “hidden” object when you shifted your point of view. They also didn’t want to use expensive high-tech materials to try and bend light around an object. These have been the previous problems with other “invisibility” projects.
According to Choi:
“This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking.”
And they’ve done it with four lenses. Right now you can’t exactly use it to hide your Romulan spacecraft, but the practical implications of this setup are for surgery and driving, to eliminate blind spots. Obviously right now the setup has limitations, like the on-axis region which can’t be hidden — meaning it’s a donut-shaped cloak. But Choi and Howell have already begun devising solutions to get around these problems. Currently the only other limitation is the size of the lense you can buy.
Phys.org published a tutorial for building your own device, which will set you back around $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.
via Discovery