The working principle of a time multiplexing detector: A single pulse of photons is split and recombined with various time delays producing a train of pulses with less than one photon per pulse. These pulses are send onto avalanche photo diodes producing 'click' or 'no-click' events. Counting the number of clicks gives information about the number of photons present in the initial pulse, but the exact relation between photon number distributions and measured click-statistics is complex because the click statistics are influenced by the number of beam splitters, the detector response functions and the losses in the system.
Scientists in the group of Christine Silberhorn in Paderborn and the group of Werner Vogel in Rostock have demonstrated a new method to identify nonclassical correlations between two parties sharing a quantum state. The method allows to characterize quantum states and resources in a simple and straight forward way. The results are published in Uncovering Quantum Correlations with Time-Multiplexed Click Detection, Phys. Rev. Lett. 115, 023601…
