Cloaking Device A Step Closer to Reality
Invisibility cloaks are a popular trope in fantasy and science fiction, from Lord of the Rings to Harry Potter. In the real world, scientists have been tinkering with cloaking devices for several years (using microwaves, light refraction, and other methods), but haven’t yet come up with a practical way to render objects invisible.
Now if you’ve got something to hide, you may be able to wrap it in materials that bend light. Aside from potentially being able to render the products you engineer invisible, the research could lead to sonar innovations and contact lenses that further enhance vision.
A group of researchers at the University of Texas in Dallas are using a transparent sheet of carbon nanotubes (one-molecule-thick sheets of carbon wrapped into cylinders), the researchers found they could bend light away from an object concealed behind the device by using electrical stimulation to heat the sheet to high temperatures.
The device operates on the same principle as the classic mirage of a pool of water in the desert or on a hot road. These types of mirages occur when the air near the ground is warmer than the air above, causing light rays to bend upward instead of bounding off the surface; thus, an image of the sky appears on the ground.
“Using these nanotube sheets, concealment can be realized over the entire optical range and rapidly turned on and off at will, using either electrical heating or a pulse of electromagnetic radiation. The research results also provide useful insights into the optimization of nanotube sheets as thermoacoustic projectors for loud speaker and sonar applications, where sound is produced by heating an alternating electrical current.”
The U.S. Army has been working on its own invisibility technology, using meta-materials to bend light and deflect radar. Researchers at the University of St. Andrews, meanwhile, created a meta-material that could work within the range of visible light, overcoming a key obstacle to meta-material-based invisibility.
You can see the University of Texas device in the video below:
Source: Institute of Physics