Prof creates invisibility cloak


(Graphic by Lena Yang)
(Graphic by Lena Yang)

A University of Toronto professor and a PhD candidate have developed an invisibility cloak made out of a meta-material that allows objects to appear invisible to the human eye.

George Eleftheriades and Michael Selvanayagam have been working together to develop a new type of invisibility cloak that differs from ones that have been created in the past.

“We have been trying to create technology which will make an object invisible to radio waves,” explained Eleftheriades. “This is what we have been doing in the past year and we now have a prototype of it.”

But this isn’t the first time an invisibility cloak has been attempted.

Prior to Eleftheriades and Selvanayagam’s creation, there were invisibility cloaks that had been developed that made an object invisible at certain angles.

However, these products have not been successful in making objects fully invisible to the naked eye.

“Our way of doing this invisibility cloak is distinct from what was done before,” described Eleftheriades.

“In order to make something invisible, you have to cancel out not just from one specific direction, but the reflection of all angles.”
Eleftheriades continued to discuss the function of the newly developed invisibility cloak.

“We did this by using tiny antennas that surround the object and the antennas radiate the exact opposite of the magnetic fields that reflect back, so the reflections are cancelled out by the field radiated by the antennas.”

The cloak can make the covered object invisible for an unlimited amount of time, as long as the antennas are radiating.

Eleftheriades, Selvanayagam and the rest of their team conceived the idea about two years ago. Just about a year ago, plans regarding the invisibility cloak were finalized and this past summer they have finally experimented with the prototype.

“Our approach is that it can cloak anything that you place inside it,” he said. “This is not for visible light. The demonstration we have in the lab is only for radio waves.”

Right now there are limitations to the prototype, but Eleftheriades expressed his team’s desire to improve the cloak.

“It is done manually, but we want it to be done electronically and automatically, so it can respond to any incident or multiple incidents. In the longer time, we can scale it to other frequencies and one day to visible light,” he explained.

It is possible that the new invention of the invisibility cloak could be used for security applications, but also may have a consumer purpose.

“We see the improvement of reception of cell phones. Sometimes cell phones have low signals, but by using invisibility coding in surrounding objects, we can make this happen and reception clear,”This is just one other positive element of the invisibility technology.

Eleftheriades also described wireless signals of satellite and Internet to be of the same technology of cloaking, and therefore can implement the electromagnetic fields.

Eleftheriades concluded by saying he “would like to make this fully automatic and adaptive electronically in magnetic fields in real time.”

“This is the next big goal, and later we can adapt this technology to other frequencies.”

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