A superconducting nanowire two-photon coincidence counter with combinatorial time logic and amplitude multiplexing

Abstract

Coincidence measurement of photon pairs over a large spatial mode is crucial for revealing non-classical phenomena and advancing quantum information technologies, which usually require an increased number of time-resolved single-photon detectors. Superconducting nanowire single-photon detectors stand out for their superior detection metrics and on-chip integration feasibility. However, their array frameworks usually only enable the localization of one photon. Here we propose a two-terminal two-photon coincidence counter using superconducting nanowire transmission lines with customized delay-time series. Using combinatorial time logic and amplitude multiplexing, our device successfully resolves all 152 potential single- and two-photon events in a 16-pixel configuration. Compared with traditional superconducting single-photon detector arrays, the device also exhibits a higher dynamic range in classical low-photon-flux sampling by efficiently suppressing multi-photon distortion. This innovative array architecture showcases self-coincidence counting, scalability and straightforward readout, making it promising for large-scale on-chip coincidence measurement in quantum information processing, as well as high-dynamic-range single-photon imaging and sensing in low-light environments.