Time-magnified photon counting with 550-fs resolution

Time-resolved photon-counting plays an indispensable role in precision metrology both classical and quantum regimes. In particular, time-correlated single-photon counting (TCSPC) has been the key enabling technology for applications such as low-light fluorescence lifetime spectroscopy photon time-of-flight (ToF) 3D imaging. However, state-of-the-art TCSPC timing resolution (SPTR) is limited range of 10-100 ps by available detector technology. this paper, we experimentally demonstrate a time-magnified (TM-TCSPC) that achieves unprecedentedly short SPTR 550 fs first time with off-the-shelf detector. The TM-TCSPC can resolve ultrashort pulses 130-fs pulsewidth difference at 22-fs accuracy. When applied to ToF imaging, greatly suppresses walk error limits all imaging systems 99.2 % (130 times) thus provides high depth measurement accuracy 26 {\mu}m 3 {\mu}m, respectively.