PT Journal
AU Khosropanah, P
   Gao, JR
   Laauwen, WM
   Hajenius, M
   Klapwijk, TM
TI Low noise NbN hot electron bolometer mixer at 4.3  THz
SO Appl. Phys. Lett.
JI Appl. Phys. Lett.
PY 2007
BP 221111 (1 to 3)
VL 91
DE NbN HEB mixers; NbN; contacts cleaning
AB We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3  THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300  K at the optimum local oscillator (LO) power of 330  nW, which is about 12 times the quantum noise (hnu/2kB). Our result indicates that there is no sign of degradation of the mixing process at the superterahertz frequencies. Moreover, a measurement method is introduced which allows us for an accurate determination of the sensitivity despite LO power fluctuations.
ER