Detection of CH4 in the mid-IR using difference frequency generation with tunable diode laser spectroscopy

I. Armstrong, W. Johnstone, K. Duffin, Michael Lengden, Arup Lal Chakraborty, Keith C. Ruxton

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This paper demonstrates detection of methane using tunable diode laser spectroscopy (TDLS) through difference frequency generation (DFG) in order to address fundamental rotational-vibrational absorption lines, located around 3404 nm. Direct detection confirms that wavelength referencing of recovered lineshapes, developed for Near infra-red (Near-IR) systems, has been successfully transferred to the presented Middle infra-red (Mid-IR) system. Traditional 1f and 2f TDLS with WMS detection regimes are also functionally confirmed analogous to their Near-IR equivalents.
Original languageEnglish
Pages (from-to)1435-1442
Number of pages8
JournalJournal of Lightwave Technology
Issue number10
Publication statusPublished - 15 May 2010


  • carbon compounds
  • chemical variables measurement
  • measurement by laser beam
  • optical harmonic generation

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