For 110 years, the scientific community has understood that light behaves as both a particle and a wave. Einstein won a Nobel Prize for this theory, and experiments have since confirmed light is a both a wave and a particle. However, until recently light’s dual characteristics had never been observed simultaneously.
In a breakthrough, researchers at the École Polytechnique Fédérale de Lausanne (EPFL) in Sweden have captured a photograph of light acting as both a wave and a particle. In order to catch light in the act, the EPFL team took advantage of the way that electrons interact with light.
They fired a pulse of laser light at a metallic nanowire, which added energy to the charged particles in the wire and caused them to vibrate, trapping the light there as a standing wave. Then they shot a stream of electrons just past the wire holding the trapped light. The electrons then hit the photons and change speed. Using an ultrafast energy-filtered transmission electron microscope – one of the two in the world—the researchers were able to pinpoint the location of the exchange of energy and take a photo. The image shows light acting simultaneously as both a wave and a particle and demonstrates for the first time ever that we can film quantum mechanics directly, which could have future applications in quantum computing.
The details of the experiment are freely available in a paper that published on March 2 in Nature Communications.