Sensitivity of a hot electron bolometer heterodyne receiver at 4.3 THz

Sensitivity of a hot electron bolometer heterodyne receiver at 4.3 THz

Khosropanah, P.
Laauwen, W.M.
Hajenius, M.
Gao, J.R.
Klapwijk, T.M.

Applied Sciences

Kavli Institute of Nanoscience

2008-08-28

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 (h?/2kB). Our result indicates that there is no sign of degradation of the mixing process at the super-THz frequencies. Also, a measurement method is introduced where the hot/cold response of the receiver is recorded at constant voltage bias of the mixer, while varying the LO power. We argue that this method provides an accurate measurement of the receiver noise temperature, which is not influenced by the LO power fluctuations and the direct detection effect. Moreover, our sensitivity data suggests that one can achieve a receiver noise temperature of 1420 K at the frequency of [OI] line (4.7 THz), which is scaled from the sensitivity at 4.3 THz with frequency.

hot electron bolometer
HEB
heterodyne receiver
THz
NbN

http://resolver.tudelft.nl/uuid:6ebb7251-5f2e-442c-93bb-0d203161fc8e

SPIE

0277-786X

Proceedings of SPIE, 2008 vol. 7020

Institutional Repository

conference paper

(c) 2008 Khosropanah, P., Laauwen, W.M., Hajenius, M., Gao, J.R., Klapwijk, T.M.