Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator
Name
Ren-2010-Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator.pdf
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1.69 MB
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Checksum (MD5)
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Author(s)
Ren, Y.
Gao, J. R.
Hovenier, J. N.
Higgins, R.
Zhang, W.
Bell, A.
Klein, B.
Klapwijk, T. M.
Shi, S. C.
Kao, Tsung-Yu
Date Issued
July 2010
Journal
Proceedings of SPIE--the International Society for Optical Engineering
Publisher
SPIE
Citation
Y. Ren, J. R. Gao, J. N. Hovenier, R. Higgins, W. Zhang, A. Bell, B. Klein, T. M. Klapwijk, S. C. Shi, T.-Y. Kao, S. Kumar, Q. Hu and J. L. Reno, "Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator", Proc. SPIE 7741, 774118 (2010); doi:10.1117/12.857658 © 2010 COPYRIGHT SPIE
Version
Final published version
Abstract
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.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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DOI of Published Version
https://doi.org/10.1117/12.857658
