Recently, it has been shown that so-called "superconducting nanowire single photon detectors" (SNSPD) can not only provide information about the presence or absence of photons, but also resolve the number of incident photons in a laser pulse. In this work, we investigated where this photon-number information is located on the electrical output signal (trace) of the SNSPD and how it can be best retrieved in an experiment. We did this by recording over one million electrical traces and applying a tool from multivariate statistics known as principal component analysis (PCA) on this large data set. With this we could reduce the complexity of the data set and locate the photon-number information on the electrical trace.
Thanks to the groups from Prof. Silberhorn and Prof. Jöns for lending some equipment, which made this work possible.
Our work "Electrical trace analysis of superconducting nanowire photon-number-resolving detectors" was published open access in Physical Review Applied and can be found here:
https://doi.org/10.1103/PhysRevApplied.22.014024
