Scientists Invent Cloak of Invisibility

Photo courtesy: dailymail

It sounds like a far-fetched invention from science-fiction or fairy tales.

But US scientists have developed a working invisibility cloak made from small particles of glass.

When light hits an object, it bounces off the surface and into the naked eye, making it visible.

But researchers at Michigan Tech University have found a way of capturing infrared light and bending it around an object, making it invisible.

At the moment the science is still based in the lab. But if the same results could be achieved with visible light, the shrouded object would disappear from sight.

Professor Elena Semouchkina has developed a nonmetallic cloak that uses identical glass resonators made of chalcogenide glass, a type of material that does not conduct electricity.

In computer simulations, the cloak made objects hit by infrared waves—approximately one micron or one-millionth of a metre long—disappear from view.

It is the first time scientists have tried using glass to bend light in this way.

Her invisibility cloak uses metamaterials, which are artificial materials with properties that do not exist in nature. These metamaterials are made of tiny glass resonators arranged in a concentric pattern in the shape of a cylinder.

The 'spokes' of the circle produce magnetic resonance which bends light waves around an object, making it invisible.

Metamaterials, which use small resonators instead of atoms or molecules of natural materials, straddle the boundary between materials science and electrical engineering.

The team is now testing an invisibility cloak rescaled to work at microwave frequencies and made of ceramic resonators.

They are carrying out the work in Michigan Tech's anechoic chamber: a cave-like compartment lined with highly absorbent charcoal-gray foam cones.

Inside, antennas transmit receive microwaves, which are much longer than infrared light, up to several centimeters long.

They have cloaked metal cylinders two to three inches in diameter and three to four inches high.

"Starting from these experiments, we want to move to higher frequencies and smaller wavelengths", the researchers said.

"The most exciting applications will be at the frequencies of visible light."

New Scientist magazine predicted last year that invisibility cloaks could be part of everyday life in 30 years.

The research appeared in the journal Applied Physics Letters, published by the American Institute of Physics.

Via dailymail