Terahertz heterodyne mixing with a hot electron bolometer and a quantum cascade laser

Terahertz heterodyne mixing with a hot electron bolometer and a quantum cascade laser

Hajenius, M.

Klapwijk, T.M. (promotor)
Gao, J.R. (promotor)

Applied Sciences

2007-01-19

Heterodyne measurements in the frequency range between 1 - 6 terahertz (THz) are expected to provide a wealth of information on questions ranging from the formation of new stars and the conditions under which life formed on our own planet to the ozone hole in our own atmosphere. Hot electron bolometers (HEB) are currently the only suitable mixers for this frequency range when very high sensitivity is required or few LO power is available. In this work space-qualified small volume twin-slot antenna coupled HEBs were developed. Such a mixer was the subject of a complete characterization in an actual receiver system based on the HEB and a tunable solid state LO source. The LO power requirement at the HEB was as low as 25 nW; enabling the receiver to operate along the full tuning range of the solid state LO source up to 2 THz. To explore sensitive heterodyne detection beyond 2 THz we demonstrated a receiver system based on an improved spiral antenna coupled HEB in combination with a novel surface plasmon quantum cascade laser (QCL) as LO source. The uncorrected sensitivity at 2.8 THz equaled 1050 K, which is the highest sensitivity at such a frequency. Most importantly, this result demonstrated that high resolution heterodyne spectroscopy can now be extended into the 2 to 6 THz range because QCL's can be designed to operate at any desired fixed frequency above 2 THz (in contrast to the existing gas lasers).

heterodyne terahertz receiver
thz
spectroscopy
hot electron bolometer
heb
quantum cascade laser
qcl

http://resolver.tudelft.nl/uuid:5536e10e-2dc5-4d45-a43a-65df4db882af

Institutional Repository

doctoral thesis

(c) 2006 M. Hajenius