Hot-spot relaxation time current dependence in niobium nitride waveguide-integrated superconducting nanowire single-photon detectors.

Author(s) Ferrari, S.; Kovalyuk, V.; Hartmann, W.; Vetter, A.; Kahl, O.; Lee, C.; Korneev, A.; Rockstuhl, C.; Gol'tsman, G.; Pernice, W.
Journal Opt Express
Date Published 2017 Apr 17

We investigate how the bias current affects the hot-spot relaxation dynamics in niobium nitride. We use for this purpose a near-infrared pump-probe technique on a waveguide-integrated superconducting nanowire single-photon detector driven in the two-photon regime. We observe a strong increase in the picosecond relaxation time for higher bias currents. A minimum relaxation time of (22 ± 1) ps is obtained when applying a bias current of 50% of the switching current at 1.7 K bath temperature. We also propose a practical approach to accurately estimate the photon detection regimes based on the reconstruction of the measured detector tomography at different bias currents and for different illumination conditions.

DOI 10.1364/OE.25.008739
ISSN 1094-4087
Citation Opt Express. 2017;25(8):87398750.

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