A Michigan Technological University scientist has worked on making an invisibility cloak, and who knows one day you might just be the owner of one!
Elena Semouchkina, an associate professor of electrical and computer engineering at Michigan Tech, has found ways to use magnetic resonance to capture rays of visible light and route them around objects, rendering those objects invisible to the human eye.
In a paper appearing in the journal Applied Physics Letters, Semouchkina and colleagues describe developing a nonmetallic cloak that uses identical glass resonators made of chalcogenide glass, a type of dielectric material (one that does not conduct electricity). In computer simulations, the cloak made objects hit by infrared waves - approximately one micron or one-millionth of a meter long - disappear from view.
Earlier attempts by other researchers used metal rings and wires.
Semouchkina said: "Ours is the first to do the cloaking of cylindrical objects with glass."
Her invisibility cloak uses metamaterials, which are artificial materials having properties that do not exist in nature, made of tiny glass resonators arranged in a concentric pattern in the shape of a cylinder. The "spokes" of the concentric configuration produce the magnetic resonance required to bend light waves around an object, making it invisible.
Semouchkina and her team now are testing an invisibility cloak rescaled to work at mocrowave frequencies and made of ceramic resonators. They're using Michigan Tech's anechoic chamber, a cave-like compartment in an Electrical Energy Resources Center lab, lined with highly absorbent charcoal-gray foam cones.
There, antennas transmit and 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.
Semouchkina said: "Starting from these experiments, we want to move to higher frequencies and smaller wavelengths. The most exciting applications will be at the frequencies of visible light."
Asked if some day the police could cloak a swat team or the Army, a tank, Semouchkina replied: "It is possible in principle, but not at this time."