High efficiency, large-active-area superconducting nanowire single-photon detectors

Gu Min^a), Zhang La-Bao^a), Kang Lin^a)†, Zhao Qing-Yuan^a), Jia Tao^a), Wan Chao^a), Xu Rui-Ying^a), Yang Xiao-Zhong^a), Wu Pei-Heng^a), Zhang Yong^b), Xia Jin-Song^b)

(a) System detection efficiency (SDE) and dark count rate versus bias current for 6-nm thick SNSPDs with a 30 μm × 30 μm active area of 100-nm width nanowires spaced at 100 nm. The SDE was 72.4% with DCR of 100 c/s under a bias current of 8.3 μ A, at 1550-nm wavelength, and the measured maximum SDE (SDE_max) was 77.2% at the DCR of ∼ 600 cps. The potential maximum SDE of this device is 79.1% evaluated from fitting by a sigmoid function. (b) The SDE of the device at different wavelengths ranging from 1064 nm to 1650 nm. The highest SDE measured, which is 81.2% when the DCR is ∼ 700 c/s appeared at the wavelength of 1650 nm.