Inter-pixel cross-talk as background to two-photon interference effects in SPAD arrays

TL;DR

This paper characterizes inter-pixel cross-talk in SPAD arrays, demonstrating its impact on two-photon interference measurements and providing calibration data for the LinoSPAD2 detector.

Contribution

It provides the first detailed measurement and analysis of inter-pixel cross-talk in SPAD arrays, especially in the context of two-photon interference experiments.

Findings

Average cross-talk probability of 0.22% for nearest neighbors

Long-range cross-talk of 2×10⁻⁵% observed up to 20 pixels apart

Cross-talk can mimic two-photon signals, affecting quantum optics measurements

Abstract

Cross-talk is a well-known feature of single-photon avalanche detectors. It is especially important to account for this effect in applications involving coincidences of two or more photons registered by the sensor since in this case the cross-talk may mimic the useful signal. In this work, we characterize the cross-talk of the LinoSPAD2 detector, as well as perform joint measurements of the cross-talk and Hanbury Brown - Twiss two-photon interference, comparing and cross-calibrating both effects. With a median dark count rate of 125 cps/pixel, we report the average cross-talk probability of $0.22~\%$ for the nearest neighbor and also observe a long-range cross-talk of the order $2 \cdot 10^{-5}~\%$ for channels separated by up to 20 pixels.