Submillimeter spectroscopy for chemical analysis with absolute specificity

Department of Physics, Ohio State University, 191 W. Woodruff Avenue, Columbus, Ohio 43210, USA.
Optics Letters (Impact Factor: 3.29). 05/2010; 35(10):1533-5. DOI: 10.1364/OL.35.001533
Source: PubMed


A sensor based on rotational signatures in the submillimeter (SMM) region is described. This sensor uses frequency synthesis techniques in the region around 10 GHz, with nonlinear diode frequency multiplication to 210-270 GHz. This provides not only a nearly ideal instrument function, but also frequency control and agility that significantly enhance the performance of the spectrometer as a sensor. The SMM frequencies provide significantly stronger absorptions and broader spectroscopic coverage than lower-frequency microwave systems. Among the characteristics of the sensor are absolute specificity, low atmospheric clutter, good sensitivity, and near-term paths to systems that are both compact and very inexpensive.

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Available from: Christopher F. Neese, Feb 13, 2015
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    • "The spectra measured by IR remote sensing techniques are associated with vibrational modes of constituent intramolecular bonds that must be interpreted in order to identify the analyte. By contrast, molecular rotational spectroscopy in the terahertz (THz)-frequency region reliably identifies the composition in most low-pressure gas mixtures [6], but its detection and recognition specificity at atmospheric pressures is greatly reduced by pressure broadening of the spectral features [7]. A remote sensing methodology based on IR-THz doubleresonance (DR) spectroscopy has been recently shown to overcome these limitations by achieving precise molecular recognition specificity, even discriminating isotopomers, at distances up to 1 km [7] [8]. "
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