Fractal superconducting nanowire single-photon detectors working in dual bands and their applications in free-space and underwater hybrid LIDAR

We demonstrate a fiber-coupled fractal superconducting nanowire single-photon detector (SNSPD) system with minimum polarization dependence of detection efficiency. Its system detection efficiency (SDE) was maximized at the wavelength of 1540 nm, which was measured to be 91 +/- 4%; furthermore, we observed the second local maximum of SDE at the wavelength of 520 nm, which was measured to be 61 +/- 2%. This dual-band feature of SDE was due to the enhancement of the optical absorptance by two longitudinal resonance modes of the micro-cavity. By using high SDE with minimum polarization dependence in these two bands, we implemented a hybrid LIDAR for imaging the remote objects in free space and under water. (c) 2023 Optica Publishing Group

Automated summary

We present a fiber-coupled fractal superconducting nanowire single-photon detector (SNSPD) system with minimal polarization dependence in detection efficiency. The system detection efficiency (SDE) was maximized at 1540 nm wavelength, with a measured value of 91 +/- 4%; moreover, we observed a second local maximum of SDE at 520 nm wavelength, with a measured value of 61 +/- 2%. This dual-band feature is attributed to the enhancement of optical absorptance by two longitudinal resonance modes of the micro-cavity. By utilizing high SDE with minimal polarization dependence in these two bands, we successfully implemented a hybrid LIDAR for imaging remote objects in free space and underwater.