Wavelength dependence of intrinsic detection efficiency of NbN superconducting nanowire single-photon detector

Wang Yong^{1, 2, 3}, Li Hao^{1, 3, †}, You Li-Xing^{1, 3, ‡}, Lv Chao-Lin^{1, 2, 3}, Wang He-Qing^{1, 2, 3}, Zhang Xing-Yu^{1, 2, 3}, Zhang Wei-Jun^{1, 3}, Zhou Hui^{1, 3}, Zhang Lu^{1, 2, 3}, Yang Xiao-Yan^{1, 3}, Wang Zhen^{1, 3}

(a) Schematic of a superconducting nanowire single-photon detector. (b) Scanning electron microscopy image of the surface topography of the NbN device. The active diameter of the device is 5μm. The inset shows a magnified image of a nanowire with width and pitch of 60 nm and 150 nm, respectively.