Enhanced Photon Number Resolution (PNR): optimizing signal chain and software capabilities

Photon Number Resolution (PNR) is the capability to determine the accurate number of photons detected by a photon detector such as Superconducting Nanowire Single-Photon Detectors (SNSPDs) in a single event. The ability to accurately resolve photon numbers is crucial for a wide range of advanced applications in photonics and quantum information science. While pulse separation to many detectors is a generic approach (pseudo-PNR), SNSPDs can be combined with advanced Time Correlated Single Photon Counting (TCSPC) electronics to obtain PNR with high sensitivity. Accurate PNR measurements require meticulous optimization of the signal chain, powerful software tools, advanced triggering capabilities, and precise calibration techniques. This work focuses on improving PNR capabilities by optimizing the entire data acquisition system, including the initial signal detection via state-of-the-art Quantum Opus SNSPDs and the accompanying data analysis architecture via picosecond-resolution Swabian Instruments’ Time Taggers. Improving photon number distinguishability paves the way for advanced quantum photonics research.