Scientists Improve Upon Existing Designs of Invisibility Cloak

UCSD researchers released a design for a working invisibility cloak that has the ability to hide objects sitting on a flat surface this past July. Unlike previous designs, UCSD’s development of the technology has been called a new step toward invisibility. Principal Investigator and Engineering Professor Boubacar Kante is in the process of submitting a proposal to the U.S. Department of Defense. 

Kante told the UCSD Guardian that research focused on the efficiency and size of the cloaking device.

“I knew the challenges in [this] area. When you wanted to cloak an object, the thing you had to put on top of it was too big,” Kante said. “So we have been thinking of ways to decrease the size of these cloaking devices.”

After putting together a team, the group used computer-aided design software to model the designs and simulate how the cloak would interact with electromagnetic waves. 

When starting this project, Kante acquired the help of both graduate and undergraduate students in the electrical and computer engineering departments. 

“It’s really important for students to be involved in research so they can be exposed to ideas and can [contribute] ideas,” Kante said. “We have three [undergraduate] students who are coming to group meetings and working on the project.”

In most previous attempts, the reflected light from the cloak was dimmer than the light that had hit the surface, leading to a noticeable difference in intensities.These cloaks were referred to as “lossy” because they lose light or brightness as it reflects back to the viewer. However, the new research avoids this issue.

“What we have achieved in this study is a ‘lossless’ cloak,” Kante told UCSD News Center. “It won’t lose any intensity of the light that it reflects.” 

The team’s goal was to scatter the waves of both light and radar to render the object without diminishing the intensity of light being reflected. To accomplish this, the researchers used a thin sheet of teflon and ceramic cylinders of differing sizes, which results in these cloaks being significantly lighter and thinner than earlier versions. In the device, the differing heights of the cylinders worked to control the light over a surface and reduce an object’s shadow. Their project was specifically a “carpet cloak,” meaning it was set over an object lying on a flat surface but appeared to reflect a flat surface. 

Besides applications in the defense industry, this technology has implications for the energy industry as well. Kante explained to the Guardian that their research could help eliminate the need for solar cells and mirrors to track with the sun and could make energy collection more efficient. 

“We could use this type of device to improve solar cells or collect light from the sun and focus that light to a line or point,” Kante said. “Also, cosmetic and design companies are interested in using [these] devices to make objects look different than they are.”

Kante discussed the idea that, though the idea of invisibility is inconceivable today, technological advances like his team’s could expedite the process of actualization.

“Invisibility may seem like magic at first, but its underlying concepts are familiar to everyone. All it requires is a clever manipulation of our perception,” Kante told the UCSD News Center. “Full invisibility still seems beyond reach today, but it might become a reality in the near future, thanks to recent progress in cloaking devices.”

The team’s conclusions were published in the Progress In Electromagnetics Research, a journal for peer-reviewed papers dealing with electromagnetic waves.