Near-zero distortion in TCSPC at more than one photon per excitation period: experimental validation.

The time-correlated single-photon counting (TCSPC) technique is widely renowned for its capability of reconstructing rapid and weak light signals with exceptional sensitivity and sub-picosecond timing resolution. Unfortunately, the speed of TCSPC has been historically severely limited to avoid a phenomenon known as pileup distortion. For this reason, the count rate of a classic TCSPC acquisition channel is kept below a few percent of the laser excitation rate (usually 1%-5%).