Many systems envisioned for practical quantum information processing require the use of single, indistinguishable photons as carriers of information and logic operators. So researchers in the field need to be certain that their light sources can dependably produce individual photons in identical states.
The customary method of doing so involves analyzing temporal differences between photons generated by laser excitation pulses, and treats those differences as a static process. That is, only differences between photon detections are analyzed, and it does not matter when in the emission cycle the photons are detected.
But PML scientists recently devised a new method of examining the output of single quantum emitters, and discovered that in many situations the differences between photon events are not static, and thus both single-photon “purity” and consecutive-photon indistinguishability fluctuate dynamically over excitation-emission time scales. They also created a model to explain the physics of the phenomenon.
Read more at: Phys.org