  We developed a time-correlated single-photon counting (TCSPC) system based on
the low-jitter superconducting nanowire single-photon detection (SNSPD)
technology. The causes of jitters in the TCSPC system were analyzed. Owing to
the low jitter of the SNSPD technology, a system jitter of 26.8 ps full-width
at half-maximum was achieved after optimizing the system. We demonstrated
time-of-flight laser ranging at 1550 nm wavelength at a stand-off distance of
115 m, based on this TCSPC system. A depth resolution of 4 mm was achieved
directly by locating the centroids of each of the two return signals. Laser
imaging was also performed using the TCSPC system. This low-jitter TCSPC system
using the SNSPD technology presents great potential in long-range measurements
and imaging applications for low-energy-level and eye-safe laser systems
