Researchers compress light to advance optical communications

  • Published
  • By Maria Callier
  • Air Force Office of Scientific Research
ARLINGTON, Va. --  Air Force Office of Scientific Research-funded scientists at the University of California at Berkeley fabricated a new type of metamaterial that bends light backwards, in a way that does not exist in nature. Such metamaterial compresses light into tighter spaces and improves optical communication, computation and detection, and camouflage capabilities.
 
An optics research team led by Dr. Xiang Zhang, a UCB mechanical engineering professor, created the new material by using metal nanowire arrays embedded in porous aluminum oxide. This work was published in the August issue of Science magazine. 

"We apply new physics in our research because metamaterials are facing difficulties in both energy loss and large-scale fabrication," Zhang said. "We are able to use non-resonant metamaterials to achieve negative refraction and that helps reduce energy loss while light passes through the metamaterial," he said. 

The team uses a bottom-up fabrication technique to make the metamaterials. They also use electro-chemical methods to grow silver nanowires inside nano-pores in macroscopic -sized aluminum oxide. 

"We take advantage of this special technique by fabricating bulk metamaterials. Although invented and already used by chemists, our method brings new perspective to the metamaterial field and proves its feasibility," Zhang said. 

In a separate AFOSR-funded work by the same researchers, published in Nature Photonics, the scientists proposed a novel waveguide scheme with the ability to pass light through a space 400 times smaller than the width of a human hair and confining light in a space that is 10 nanometers. 

Rupert Oulton, research associate on Zhang's team noted in the UCB article, "New Technique to Compress Light Could Open Doors for Optical Communications," that many researchers want to link electronics with optics, but so far, have been unsuccessful because the two are on different scales. 

"Currently, we are trying to use metamaterials to achieve sub-wavelength imaging. Because of their novelty, we are still exploring their many properties and do not fully understand the extent of their possible applications, many of which will be of help to the high-tech Air Force of the future," Zhang said. He concluded, "Innovations in metamaterials are expected to significantly affect the way the Air Force carries out its military tasks now and in the future."