  Superconducting nanowire single-photon detectors (SNSPDs) at a wavelength of
532 nm were designed and fabricated aiming to satellite laser ranging (SLR)
applications. The NbN SNSPDs were fabricated on one-dimensional photonic
crystals with a sensitive-area diameter of 42 um. The devices were coupled with
multimode fiber (phi=50um) and exhibited a maximum system detection efficiency
of 75% at an extremely low dark count rate of <0.1 Hz. An SLR experiment using
an SNSPD at a wavelength of 532 nm was successfully demonstrated. The results
showed a depth ranging with a precision of ~8.0 mm for the target satellite
LARES, which is ~3,000 km away from the ground ranging station at the Sheshan
Observatory.
