High-speed TCSPC measurements: achieving multiphoton detection per excitation period with near-zero distortion

Historically, Time Correlated Single Photon Counting (TCSPC) has been hindered by a critical tradeoff between speed and distortion. Classical theory dictates that accurate light waveform reconstruction requires the detector count rate to be limited to 1-5% of the laser frequency, making TCSPC inherently slow. Efforts to speed up TCSPC, such as multichannel systems, post-processing algorithms for pile-up correction, and the exploitation of faster Single Photon Avalanche Diodes (SPADs), often face implementation and application-specific challenges. In this work, we present the first experimental validation of a novel TCSPC approach that overcomes detector dead time and illumination intensity limitations, achieving high-speed operation without pile-up distortion. By combining real-time system status information with classic TCSPC data, we reach an unprecedented count rate of 60% of the excitation frequency with near-zero distortion using off-the-shelf modules.