Scientists open door to manipulating ‘quantum light’
Light particles, also called photons, do not normally interact with each other. An international research team has now demonstrated for the first time that a few photons can be manipulated and made to interact in a controlled manner. This could advance both medical imaging and quantum computing.
21 March 2023
Photons do not interact with each other in a vacuum: they fly through one another undisturbed. This makes them valuable for data transfer because information can be transported at the speed of light almost without interference. Light is useful not only for data transmission, but also in certain measuring instruments because it can be used to determine tiny distances, for example in medical imaging. The sensitivity of such instruments depends on the average number of photons in the system.
Even though photons do not interact with each other, they do interact with materials, for example when they pass through glass. This interaction is normally independent of the intensity of the light. Only when very high energy laser light is used does the intensity affect the interaction.
Such an intensity effect for just two photons is described by a team from the University of Basel, the University of Sydney and the Ruhr-Universität Bochum in the journal Nature Physics. They demonstrated that a single photon flew through their measuring instrument more slowly than two photons.