A complete set of characterizations on the NbN superconducting nanowire single photon detectors

The recent advancement on niobium nitride (NbN) superconducting nanowire single photon detectors (SNSPDs) have drawn considerable attentions by many of their particular figures of merit. In this work, we report our experimental efforts resulting from combinations of dc, RF/microwave and optoelectronic characterizations of this device. The dc IV measurement is under-taken in the full voltage bias range and four distinct regimes are recognized and discussed. The kinetic inductance measurement allows us to gain insights on the electrical properties of the NbN nanowire. An equivalent circuitry model is constructed and simulated for the photoresponse in the course of RF/Microwave S-parameter measurement. The simulated photoresponse qualitatively agrees with the experimental results. Finally we apply continuous wave irradiation to investigate the optical interactions with superconducting nanowires. A relationship between chemical potential and optical power and wavelength has been experimentally confirmed. Two regimes have been identified and physically modeled. The comparison with experimental results displays a good agreement.