PT Journal
AU Tret'yakov, IV
   Kaurova, NS
   Voronov, BM
   Anfert'ev, VA
   Revin, LS
   Vaks, VL
   Gol'tsman, GN
TI The influence of the diffusion cooling on the noise band of the superconductor NbN hot-electron bolometer operating in the terahertz range
SO Tech. Phys. Lett.
PY 2016
BP 563
EP 566
VL 42
IS 6
DI 10.1134/S1063785016060146
DE HEB; noise bandwidth; conversion gain bandwidth; noise temperature; Andreev reflection
AB Results of an experimental study of the noise temperature (Tn) and noise bandwidth (NBW) of the superconductor NbN hot-electron bolometer (HEB) mixer as a function of its temperature (Tb) are presented. It was determined that the NBW of the mixer is significantly wider at temperatures close to the critical ones (Tc) than are values measured at 4.2 K. The NBW of the mixer measured at the heterodyne frequency of 2.5 THz at temperature Tb close to Tc was ~13 GHz, as compared with 6 GHz at Tb = 4.2 K. This experiment clearly demonstrates the limitation of the thermal flow from the NbN bridge at Tb â‰<aa> Tc for mixers manufactured by the in situ technique. This limitation is close in its nature to the Andreev reflection on the superconductor/ metal boundary. In this case, the noise temperature of the studied mixer increased from 1100 to 3800 K.
ER