The superconducting nanowire single photon detector (SNSPD) has broad application prospects in the fields of quantum key distribution, deep space optical communication, quantum fingerprints, laser ranging, and imaging. Among them, the count rate is one of the key technical indicators of SNSPD. The large dynamic inductance brought by the long nanowires leads to the currently practical SNSPD count rate usually only reaching tens of MHz, but it is necessary to achieve efficient optical coupling. Related studies have shown that replacing long single nanowires with multiple arrays of individual nanowires can simultaneously reduce dynamic inductance and increase detection speed.

Recently, under the support of the key special project of the National Key R & D Program "Quantum Control and Quantum Information", You Lixing's research group at the Shanghai Institute of Microsystems and Information Technology, Chinese Academy of Sciences reported that under the low photon flux limit of 1550 nm, the use of 9 The intersecting array of nanowires achieves a high-speed SNSPD array with a system detection efficiency (SDE) of 70% and a dark count rate of 200 Hz. When the photon flux is 1.26 × 1010 photons / s, the maximum count rate reaches 0.93 GHz, and the SDE is ~ 7.4%; when the count rate is 200 MHz, the SDE exceeds 50%. This research work will help promote the development of SNSPD, making SNSPD play an important role in many cutting-edge science and application fields such as quantum key distribution and remote sensing telemetry. The research work was published in Superconductor Science and Technology on May 18, 2018.

Fig. (A) SEM photographs of nine SNSPD arrays with interlaced nanowires (the dotted circles in the figure indicate the photosensitive area with a diameter of 15 μm);
(B) SNSPD chip package box; (c) GM refrigeration system loaded with SNSPD array.