Dual personality of light caught on camera

For over a century, it has been known that light can simultaneously behave as a wave and a particle, but, until now, no one has ever caught it in the act. Light has been observed many times spread out over a succession of crests and troughs in a wave-like manner and just as many times localised within a very tiny area, as if it were a particle. However, an image of it behaving in both forms simultaneously has proven elusive.

A team of researchers led by Fabrizio Carbone at the Swiss Federal Institute of Technology in Lausanne have now successfully photographed light’s dual behaviour using an ultrafast, energy-filtered, transmission electron microscope. Only two of these instruments exist in the world.