It is well known that light is capable of acting like a particle as well as a wave. However, these have always been viewed as completely separate forms, not embodying both at once. Quantum mechanics states that light should have both attributes simultaneously, but that phenomenon has never been imaged directly until now. A team of researchers has finally been able to photograph the quantum wave-particle duality of light, and they have described the work in an open access paper published in Nature Communications. This will help researchers better understand the fundamental nature of light, and could even help assist the development of quantum computing and a number of other technologies.
The researchers created a standing wave of light after blasting a metal wire with UV light. They then shot electrons at the wave, trying to disturb individual photons. When the two particles interacted, the change in energy made the photon slow down or speed up, depending on how the connection occurred. The interaction was able to be seen with a high-powered microscope.
Because the wave is really a succession of distinct particles, the researchers were able to view the standing wave, and the photons that were disturbed were still seen as individuals.. Thus, witnessing light’s wave-particle duality became possible for the first time. Once the photons were disturbed, the researchers were then able to image the quantum change in energy, as can be seen above.
“This experiment demonstrates that, for the first time ever, we can film quantum mechanics – and its paradoxical nature – directly,” senior author Fabrizio Carbone from École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland said in a press release. “Being able to image and control quantum phenomena at the nanometer scale like this opens up a new route towards quantum computing.”
The photoelectric principles that allowed the researchers to finally image the wave-particle duality of light were first proposed by Albert Einstein at the turn of the 20th century, when light was only believed to be a wave. Einstein suggested that the waves were actually composed of a stream of individual particles, which wasn’t very popular initially. However, this work would eventually lead to Einstein receiving the Nobel Prize in Physics in 1921.