PT Journal
AU Zhang, J
   Słysz, W
   Pearlman, A
   Verevkin, A
   Sobolewski, R
   Okunev, O
   Chulkova, G
   Gol’tsman, GN
TI Time delay of resistive-state formation in superconducting stripes excited by single optical photons
SO Phys. Rev. B
JI Phys. Rev. B
PY 2003
BP 132508 (1 to 4)
VL 67
IS 13
DI 10.1103/PhysRevB.67.132508
DE NbN SSPD; SNSPD
AB We have observed a 65(±5)-ps time delay in the onset of a resistive-state formation in 10-nm-thick, 130-nm-wide NbN superconducting stripes exposed to single photons. The delay in the photoresponse decreased to zero when the stripe was irradiated by multi-photon (classical) optical pulses. Our NbN structures were kept at 4.2 K, well below the material’s critical temperature, and were illuminated by 100-fs-wide optical pulses. The time-delay phenomenon has been explained within the framework of a model based on photon-induced generation of a hotspot in the superconducting stripe and subsequent, supercurrent-assisted, resistive-state formation across the entire stripe cross section. The measured time delays in both the single-photon and two-photon detection regimes agree well with theoretical predictions of the resistive-state dynamics in one-dimensional superconducting stripes.
ER