Superconducting Nanowire Single-Photon Detectors at a Wavelength of 2000 nm

In this article, we demonstrate a superconducting nanowire single photon detector (SNSPD) at a wavelength of 2000 nm. We use numerical simulations to optimize the parameters of the device structure. Guided by the obtained numerical results, we fabricated and measured the device that operates at 2000 nm at 2.3K. The results indicate that our device responses well in 2000nm with a dark count rate of 100Hz. The recovering time is 100ns.