Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator

Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator

Ren, Y.
Gao, J.R.
Hovenier, J.N.Higgins, R.
Zhang, W.
Bell, A.
Klein, B.
Klapwijk, T.M.

Applied Sciences

Kavli Institute of Nanoscience

2010-12-31

High-resolution heterodyne spectrometers operating at above 2 THz are crucial for detecting, e.g., the HD line at 2.7 THz and oxygen OI line at 4.7 THz in astronomy. The potential receiver technology is a combination of a hot electron bolometer (HEB) mixer and a THz quantum cascade laser (QCL) local oscillator (LO).Here we report the first highresolution heterodyne spectroscopy measurement of a gas cell using such a HEB-QCL receiver. The receiver employs a 2.9 THz free-running QCL as local oscillator and a NbN HEB as a mixer. By using methanol (CH3OH) gas as a signal source, we successfully recorded the methanol emission line at 2.92195 THz. Spectral lines at IF frequency at different pressures were measured using a FFTS and well fitted with a Lorentzian profile. Our gas cell measurement is a crucial demonstration of the QCL as LO for practical heterodyne instruments. Together with our other experimental demonstrations, such as using a QCL at 70 K to operate a HEB mixer and the phase locking of a QCL such a receiver is in principle ready for a next step, which is to build a real instrument for any balloon-, air-, and space-borne observatory.

THz quantum cascade laser, superconducting HEB mixer, heterodyne spectroscopy

http://resolver.tudelft.nl/uuid:6796de1a-46ce-4119-b868-504be5536c0c

https://doi.org/10.1117/12.857658

SPIE

0277-786X

Proceedings of SPIE, 2010 vol. 7741

Institutional Repository

conference paper

(c)2010 The Authors