Quantum detector tomography of a superconducting nanostrip photon-number-resolving detector

Superconducting nanostrip photon detectors have been used as single detectors, which can discriminate only photons' presence or absence. It has recently found that they the number of photons by analyzing output signal waveform, and are expected to be in various fields, especially optical quantum information processing. Here, we improve photon-number-resolving performance for light with a high-average pattern matching waveform. Furthermore, estimate positive-operator-valued measure detector tomography. The result shows device up five without any multiplexing arraying, indicating it is useful detector.