A large active area no longer equals low performance for superconducting nanowire single-photon detectors

JUL 19, 2019

New design for a superconducting nanowire single-photon detector yields a large active area 300 micrometers in diameter while meeting the high count rate and detection efficiency values required for LIDAR applications.

Chris Patrick

DOI: 10.1063/1.5120176

A large active area no longer equals low performance for superconducting nanowire single-photon detectors internal name — A large active area no longer equals low performance for superconducting nanowire single-photon detectors lead image

Existing superconducting nanowire single-photon detectors (SNSPDs) have a small active area and perform well in various quantum applications including quantum optics, quantum computing and long-distance quantum key distribution.

SNSPDs with larger active areas have potential applications in light detection and ranging (LIDAR), deep space communication and astronomy. But it’s difficult to increase the active area of an SNSPD without suppressing its count rate, a measure of device performance. The probability of defects also increases with the nanowire length, which may decrease the nanowire’s detection efficiency.

Zhang et al. designed and fabricated a niobium nitride SNSPD with a large active area 300 micrometers in diameter. When the authors tested the count rate and detection efficiency of their device, they found that these measures of performance met LIDAR system requirements.

The new device possesses a circular active area made up of nine individual parts. Each part consists of two superconducting nanowire avalanche photodetectors, which reduces the kinetic inductance of each part by fourfold, therefore increasing the maximal count rate of the device. The authors also boosted the detection efficiency of the device by employing electron-beam lithography to manufacture nanowires with good uniformity. Combining several approaches allowed them to make a high performance SNSPD with a large active area.

Author Lixing You said that there is generally no count rate or detection efficiency limit for SNSPDs, but making the system user friendly remains the key barrier for this technology.

Source: “NbN superconducting nanowire single-photon detector with an active area of 300 µm-in-diameter,” by Chengjun Zhang, Weijun Zhang, Jia Huang, Lixing You, Hao Li, Chaolin Lv, Tatsuki Sugihara, Masahiko Watanabe, Hui Zhou, Zhen Wang, and Xiaoming Xie, AIP Advances (2019). The article can be accessed at https://doi.org/10.1063/1.5095842 .