PT Journal
AU Pentin, I
   Finkel, M
   Maslennikov, S
   Vakhtomin, Y
   Smirnov, K
   Kaurova, N
   Goltsman, G
TI Superconducting hot-electron-bolometer mixers for the mid-IR
SO Rus. J. Radio Electron.
JI Rus. J. Radio Electron.
PY 2017
IS 10
LA Russian
DE IR NbN HEB mixers
AB The work presents the result of development of the NbN superconducting hot-electron-bolometer (HEB) mixer. The sensitive element of the mixer is directly coupled to mid-IR radiation, and doesn’t have planar metallic antenna. Investigations of noise characteristics of NbN HEB mixer were performed at the frequency 28.4 THz (λ = 10.6 µm) by using gas-discharge CW CO2-laser without consideration of optical and electrical losses in the heterodyne receiver. The noise temperature of NbN HEB mixer with the size of the sensitive element 10 µm × 10 µm was 2320 K (~ 1.5hν/kB) at the heterodyne frequency of 28.4 THz. The noise temperature was determined by measuring the Y-factor taking into account the term which describes fluctuations of zero-point oscillations in accordance with the fluctuation-dissipation theorem of Calle-Welton. Isothermal method was used to estimate the absorbed heterodyne radiation power which was 9 µW at the optimal operating point for the minimum noise temperature of NbN HEB mixer.
ER