PT Journal
AU Zhang, W
   Khosropanah, P
   Gao, JR
   Kollberg, EL
   Yngvesson, KS
   Bansal, T
   Barends, R
   Klapwijk, TM
TI Quantum noise in a terahertz hot electron bolometer mixer
SO Applied Physics Letters
JI Appl. Phys. Lett.
PY 2010
BP 111113-(1-3)
VL 96
IS 11
DE HEB mixer; quantum limit; quantum noise; vacuum box; THz; Terahertz
AB We have measured the noise temperature of a single, sensitive superconducting NbN hot electron bolometer (HEB) mixer in a frequency range from 1.6 to 5.3 THz, using a setup with all the key components in vacuum. By analyzing the measured receiver noise temperature using a quantum noise (QN) model for HEB mixers, we confirm the effect of QN. The QN is found to be responsible for about half of the receiver noise at the highest frequency in our measurements. The beta-factor (the quantum efficiency of the HEB) obtained experimentally agrees reasonably well with the calculated value.
ER