Researchers have discovered a new metamaterial, potentially making it possible for invisibility cloaks to become a reality in this lifetime.
In a study published in the journal Nature Communications, Hao Xin and colleagues detailed the production of a synthetic material that puts engineers a step closer toward building microscopes featuring superlenses or shields capable of concealing aircraft and people.
In the University of Arizona where he is tenured as a computer and electrical engineering professor, Xin uses the Millimeter Wave Circuits and Antennas Laboratory to print metamaterials in 3D. Looking like tiny circuit boards of copper wire and porous plastic bowling balls, the metamaterials are configured to feature precise geometrical patterns for bending energy waves in unusual ways. They are able to bend energy waves backwards, a property called negative refraction.
Quite neat, right? Unfortunately, this property also brings problems, reducing the strength of whatever wave the metamaterial encounters.
What Xin and his colleagues did, however, was not only to produce metamaterials but also to create some that would retain the negative refraction property without causing waves to lose their strength.
In fact, they were not only able to prevent energy loss but were actually able to boost strength for a wave as it passed through the metamaterial. This was made possible by embedding simple tunnel diodes powered by batteries and micronanofabrication technology into the metamaterial.
"Many people did not think it was possible to achieve energy gain along with negative refraction," said Xin.
He was able to, first showing it was possible in 2011. His work back then was on one-dimensional metamaterials. This time around, Xin's research involved 3D metamaterials, implying broader applications in which the material may be utilized.
Aside from biomedical applications, metamaterials with both energy gain and negative refraction properties will also pave the way for improved sensor technology, higher-performance microwave circuits, more earthquake-resistant buildings and more powerful solar converters.
Metamaterials are still under testing, but Xin is confident that even with the additional years of research needed to produce a fully functional material, he will be able to see an invisibility cloak during his lifetime.
Xin presented the study's findings to Tri-Service Metamaterials Program scientists at the Duke University in November 2014. The program promotes collaboration among the industry, academia and government to advance research on metamaterials for the Department of Defense.
The study received funding support from the Air Force Office of Scientific Research. Other authors include Dexin Ye, Lixin Ran and Kihun Chang.
