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Proceedings Paper

THIS: next-generation infrared heterodyne spectrometer for remote sensing
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Paper Abstract

The Cologne spectrometer THIS (Tuneable Heterodyne Infrared Spectrometer) opens the mid-infrared wavelength region from 5 to 17 µm for ultra-high-resolution spectroscopy. With a current bandwidth of 14 km/sec and a frequency resolution of R=2*107 it is the only widely tuneable and transportable infrared heterodyne receiver. A Quantum-Cascade laser is used as local oscillator (LO). To provide optimum beam combination a Fabry-Perot ringresonator is used to superimpose the LO and the radiation. Frequency mixing is done by a Mercury-Cadmium-Telluride photomixer and spectral analysis is performed by an Acousto-Optical spectrometer. The system noise temperature is about three times the quantum limit giving THIS a sensitivity equivalent to CO2-laser based heterodyne systems. Various measurements at different ground based telescopes including the analysis of trace gases in Earth's atmosphere, observations of molecular features in sunspots, and detection of non-LTE CO2 emission from the atmosphere of Venus' have been performed and demonstrate the instrument's capabilities for astronomical observations at ground based telescopes and the stratospheric observatory SOFIA in the near future. Possible targets for future observations with THIS will be discussed.

Paper Details

Date Published: 10 November 2003
PDF: 9 pages
Proc. SPIE 5152, Infrared Spaceborne Remote Sensing XI, (10 November 2003); doi: 10.1117/12.504170
Show Author Affiliations
Daniel Wirtz, Univ. zu Koln (Germany)
Guido Sonnabend, NASA Goddard Space Flight Ctr. (United States)
Rudolf Schieder, Univ. zu Koln (Germany)

Published in SPIE Proceedings Vol. 5152:
Infrared Spaceborne Remote Sensing XI
Marija Strojnik, Editor(s)

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