PT Journal
AU Verevkin, A
   Pearlman, A
   Slysz, W
   Zhang, J
   Currie, M
   Korneev, A
   Chulkova, G
   Okunev, O
   Kouminov, P
   Smirnov, K
   Voronov, B
   Gol'tsman, GN
   Sobolewski, R
TI Ultrafast superconducting single-photon detectors for near-infrared-wavelength quantum communications
SO J. Modern Opt.
JI J. Modern Opt.
PY 2004
BP 1447
EP 1458
VL 51
IS 9-10
DI 10.1080/09500340408235284
DE NbN SSPD; SNSPD
AB The paper reports progress on the design and development of niobium-nitride, superconducting single-photon detectors (SSPDs) for ultrafast counting of near-infrared photons for secure quantum communications. The SSPDs operate in the quantum detection mode, based on photon-induced hotspot formation and subsequent appearance of a transient resistive barrier across an ultrathin and submicron-width superconducting stripe. The devices are fabricated from 3.5 nm thick NbN films and kept at cryogenic (liquid helium) temperatures inside a cryostat. The detector experimental quantum efficiency in the photon-counting mode reaches above 20% in the visible radiation range and up to 10% at the 1.3–1.55 μn infrared range. The dark counts are below 0.01 per second. The measured real-time counting rate is above 2 GHz and is limited by readout electronics (the intrinsic response time is below 30 ps). The SSPD jitter is below 18 ps, and the best-measured value of the noise-equivalent power (NEP) is 2 × 10−18 W/Hz1/2. at 1.3 μm. In terms of photon-counting efficiency and speed, these NbN SSPDs significantly outperform semiconductor avalanche photodiodes and photomultipliers.
ER