Numerical modelling of fully quantum, spontaneous parametric down conversion process and coincidence detection

WANGKai-ge, CAODezhong

Zhihan Jin, Binbin Yu, Junwei Chu +2 more

This study discusses the correction factors in detection efficiency measurements based on spontaneous parametric down-conversion (SPDC) and coincidence counting. To address the coincidence loss induced by relative delays between two detection channels, this study proposes an accurate calculation analysis based on counting probability statistics derived from coincidence events. Additionally, an approximate method utilizing histograms and the photon count rate of detectors is proposed, which can effectively reduce the errors in coincidence loss corrections. Furthermore, the study discusses the dead time of single-photon detectors (SPDs) and proposes a weighted-average method applicable for correcting the influence of dead time.

De-Zhong Cao

Liqun Sun, Yanpeng Zhang, Tiantong Tang +2 more

A new method of absolute measurement of photodetector quantum efficiency based on spontaneous parametric down- conversion (SPDC) biphoton field is discussed. The process of SPDC is studied theoretically. The single photon detection probability and two-photon coincidence probability are derived and the measurement principle of photodetectors is explained. An experimental system has been set up. The quantum efficiency of a photon-counting photomultiplier tube was measured, and the results were compared with that obtained using conventional method.

Zijun Chen, Yeshaiahu Fainman

This work presents a probability theory of coincidence detection to address the detection limit of time-correlated photon sources. We use Bayes’ theorem to model instruments as a noisy communication channel and apply statistical inference to identify the minimum detectable coincidence rate. Photon triplet generation is considered as a case study to illustrate the application of coincidence detection theory for time-correlated photon sources that are based on spontaneous parametric down-conversion. A triplet generation rate of 1–100 Hz is required for source characterization performed over 1–72 hours using superconducting nanowire single-photon detectors. We envision the connection between Bayes’ theorem and coincidence detection opens up a new avenue for applying signal processing techniques available in information theory to photon coincidence measurements.

E. Brambilla, A. Gatti, Luigi A. Lugiato +1 more