EU-funded scientists have created an antenna that captures light in the same way that TV and radios aerials capture signals. The device is an outcome of the Bio-inspired molecular optoelectronics (BIMORE) project, which received nearly €3 million under the Marie Curie Research Training Networks mobility scheme of the Sixth Framework Programme (FP6).
Researchers led by condensed matter physicist Professor Doug Natelson and graduate student Dan Ward from Rice University in the US have developed an optical antenna from two gold tips separated by a nanoscale gap — about a hundred-thousandth the width of a human hair — that gathers light from a laser.
The tips grab the light and concentrate it into a tiny space, said Natelson, leading to a thousandfold increase in light intensity in the gap. His team discovered that the key to measuring light amplification was measuring the electrical current between the gold tips.
“Putting the nanotips so close together allows charge to flow via quantum tunnelling as the electrons are pushed from one side to the other,” said the researchers. They could then get electrons moving by pushing them at low frequencies.
Natelson said that he expected the discovery to be useful in developing tools for optics and for chemical and biological sensing, even at the single-molecule scale.
Natelson said that the team studied enhanced fields because much can be done with sensors and non-linear optics.” Anything that gives you a handle on what’s happening at these tiny scales is very useful,” he said.
Contributions to the study were made by researchers from the Karlsruhe Institute of Technology in Germany and the Autonomous University of Madrid in Spain.