Resolving Multiphoton Coincidences in Single-Photon Detector Arrays with Row-Column Readouts

Row-column multiplexing has proven to be an effective strategy in scaling single-photon detector arrays to kilopixel and megapixel spatial resolutions. However, with this readout mechanism, multiphoton coincidences on the array cannot be easily resolved due to ambiguities concerning their spatial locations of incidence. In this work, we propose a method to resolve up to 4-photon coincidences in single-photon detector arrays with row-column readouts. By utilizing unambiguous single-photon measurements to estimate probabilities of detection at each pixel, we redistribute the ambiguous multiphoton counts among candidate pixel locations such that the peak signal-to-noise-ratio of the reconstruction is increased between 3 and 4 dB compared to conventional methods at optimal operating conditions. We also show that our method allows the operation of these arrays at higher incident photon fluxes as compared to previous methods. The application of this technique to imaging natural scenes is demonstrated using Monte Carlo experiments.