Invisibility Cloaks Hit the Big Time

"This is not simply an illusion," says the creator of one cloak. "Even scientific instruments will not be able to detect the object."

By Patrick Morgan
Jun 22, 2011 5:00 AMNov 12, 2019 4:31 AM
paper.jpg
A crystal invisibility cloak hides part of a rolled up piece of pink paper. Courtesy Baile Zhang, George Barbastathis/Smart Certre, Singapore | NULL

Newsletter

Sign up for our email newsletter for the latest science news
 

Until recently, every invisibility cloak developed has operated at the microscopic scale, hiding objects that were already too small to see with the naked eye. If invisibility cloaks for invisible things seem disappointing, take heart: This year two separate teams stepped up with the first devices capable of concealing objects as big as a paper clip, bringing a practical invisibility cloak within reach.

In both cases, the researchers carved out a hiding place in a crystal of the mineral calcite. Physicist Shuang Zhang and colleagues at the University of Birmingham in England hid a paper clip, while MIT engineer George Barbastathis and his team chose a rolled-up piece of paper. Both objects appeared to vanish.

The real magic is an optical property of calcite called anisotropy. The mineral splits up light rays and reflects them in such a way that it renders the chamber invisible. Of course, there is a catch. Concealment depends on light waves oscillating in the same direction, an effect that spoils most practical applications. Zhang, however, is hopeful; he believes the technology might eventually be capable of hiding humans.

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!

Subscribe

Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Stay Curious
Join
Our List

Sign up for our weekly science updates.

 
Subscribe
To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.