PT Journal
AU Gao, JR
   Hajenius, M
   Yang, ZQ
   Baselmans, JJA
   Khosropanah, P
   Barends, R
   Klapwijk, TM
TI Terahertz superconducting hot electron bolometer heterodyne receivers
SO IEEE Trans. Appl. Supercond.
PY 2007
BP 252
EP 258
VL 17
IS 2
DI 10.1109/TASC.2007.898066
DE HEB; mixer; direct detection effect
AB We highlight the progress on NbN hot electron bolometer (HEB) mixers achieved through fruitful collaboration between SRON Netherlands Institute for Space Research and Delft University of Technology, the Netherlands. This includes the best receiver noise temperatures of 700 K at 1.63 THz using a twin-slot antenna mixer and 1050 K at 2.84 THz using a spiral antenna coupled HEB mixer. The mixers are based on thin NbN films on Si and fabricated with a new contact-process and-structure. By reducing their areas HEB mixers have shown an LO power requirement as low as 30 nW. Those small HEB mixers have demonstrated equivalent sensitivity as those with large areas provided the direct detection effect due to broadband radiation is removed. To manifest that a HEB based heterodyne receiver can in practice be used at arbitrary frequencies above 2 THz, we demonstrate a 2.8 THz receiver using a THz quantum cascade laser (QCL) as local oscillator.
ER