Toward next-generation single-photon detection architectures for ultra-fast and distortion-free TCSPC-based time-resolved imaging

In modern biomedical research and clinical settings, capturing fast-evolving dynamics in real time across large areas drives the need for wide-field, high-throughput imaging systems with superior spatial and temporal resolution. Time-Correlated Single-Photon Counting (TCSPC) excels at resolving faint, rapid optical signals with picosecond precision but is limited by detector dead time, forcing operation at just 5% of the excitation rate to avoid pile-up distortion. We developed a novel approach that overcomes these constraints, enabling distortion-free waveforms reconstruction under any condition by monitoring the activity state of the detector during acquisition. Validated on systems with binary detection states, this method can achieve better performance when paired with architectures supporting non-binary detection efficiencies. To this end, we introduce a large-area, multipixel single-photon detector, where each pixel comprises an optimized number of cells. Our fully integrated front-end features sub-nanosecond dead time and smart on-chip logic, enabling multiple photon detection per cycle per pixel, greatly surpassing traditional limits for advanced time-resolved imaging.