PT Unknown
AU Merkel, HF
   Yagoubov, PA
   Kroug, M
   Khosropanah, P
   Kollberg, EL
   Gol’tsman, GN
   Gershenzon, EM
TI Noise temperature and absorbed LO power measurement methods for NbN phonon-cooled hot electron bolometric mixers at terahertz frequencies
SE Proc. 28th European Microwave Conf.
PY 1998
BP 294
EP 299
VL 1
DI 10.1109/EUMA.1998.338003
DE NbN HEB mixers
AB In this paper the absorbed LO power requirements and the noise performance of NbN based phonon-cooled hot electron bolometric (HEB) quasioptical mixers are investigated for RF frequencies in the 0.55-1.1 range The minimal measured DSB noise temperatures are about 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz and 1250 K at 1.1 THz. The increase in noise temperature at 1.1THz is attributed to water absorption. The absorbed LO power is measured using a calorimetric approach. The results are subsequently corrected for lattice heating. These values are compared to results of a novel one dimensional hot spot mixer models and to a more traditional isotherm method which tends to underestimate the absorbed LO power for small bias powers. Typically a LO power between 50nW and 100nW is needed to pump the device to the optimal operating point.
ER