Light’s Wave-Particle Duality Visualized (with video)

A novel imaging approach has brought light’s split personalities together for the first time.

The wave-particle duality of light is well known, though experiments to date have only been able to observe one property at a time. But now a team of researchers in Switzerland and the U.S. has used a specialized electron microscope to capture light behaving as both a particle and wave simultaneously.

Energy-space photography of light confined on a nanowire simultaneously shows both spatial interference and energy quantization. Courtesy of Fabrizio Carbone/EPFL.

Their experiment involved using laser pulses to create standing waves of surface plasmon polaritons on a single nanowire suspended on a graphene film. Passing electrons interacted with the confined light on the nanowire and either sped up or slowed down.

“The resulting energy exchange between single electrons and the quanta of the photoinduced near-field is imaged synchronously with its spatial interference pattern,” the researchers wrote in Nature Communications (doi: 10.1038/ncomms7407).

“This experiment demonstrates that, for the first time ever, we can film quantum mechanics — and its paradoxical nature — directly,” said professor Dr. Fabrizio Carbone of the Swiss Federal Institute of Technology in Lausanne (EPFL), who led the study.

The imaging was carried out using EPFL’s ultrafast energy-filtered transmission electron microscope, one of only two such instruments in the world. Researchers at Lawrence Livermore National Laboratory and Trinity College in Connecticut were also involved.

Carbone said the technique could help advance quantum computing.

“This methodology enables the control and visualization of plasmonic fields at the nanoscale, providing a promising tool for understanding the fundamental properties of confined electromagnetic fields and the development of advanced photonic circuits,” the researchers wrote in their study.

For more information, visit www.epfl.ch.