Imagine a vast field of fireflies, each flashing alone rather than in a swarm: that's what the new automated setup is hunting for. It sweeps a laser across the sample like a flashlight and records the color and brightness of the glow at every spot. If a single photon flashes somewhere, that's the 'firefly' needed for quantum computers and secure communication.
To tell a true single-photon source from random noise, the setup measures the same spot twice. Cosmic rays, which sometimes corrupt data, don't repeat, but a real source does. Then the found source is checked with a special instrument — the Hanbury Brown–Twiss interferometer. It counts how often photons arrive in pairs. If pairs are almost absent, the source truly emits light one photon at a time, like a gumball machine that dispenses a single ball with each turn.
The setup is controlled by a Python program that moves the sample stage, records spectra, and processes data. It can be cooled to very low temperatures — important because many quantum materials reveal their properties only in the cold. The result is maps of emission and temperature-dependent curves that help quickly assess how good a given single-photon source is.
The Hanbury Brown–Twiss interferometer was originally invented by astronomers to measure the sizes of stars, and now it helps verify quantum light sources.