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12 August 2008 Pulsed quantum cascade laser based cavity ring-down and cavity enhanced spectroscopy for the detection of ethylene.
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Proceedings Volume 7099, Photonics North 2008; 709922 (2008) https://doi.org/10.1117/12.804794
Event: Photonics North 2008, 2008, Montréal, Canada
Abstract
We investigated the use of a pulsed, distributed feedback (DFB) quantum cascade (QC) laser centered at 970 cm-1 in combination with cavity ring-down spectroscopy (CRDS) and cavity enhanced spectroscopic (CES) techniques for the detection of ethylene. In these techniques, the laser is coupled to a high-finesse cavity formed by high reflectivity mirrors. In the CRDS application, the laser frequency was tuned at a rate of ~0.071 cm-1/K by changing the heat sink temperature in the range between -20 and 50°C. For off-axis CES, the laser was excited with short current pulses (5-10 ns), and the pulse amplitude was modulated with an external current ramp which gave a frequency scan of ~0.3 cm-1. We utilized a demodulation approach followed by numerical filtering to improve the signal-to-noise ratio. Basic instrument performance and optimizations of the experimental parameters for sensitivity improvement are discussed. We demonstrated a detection limit of ~130 ppb with CRDS and ~15 ppb with off-axis CES for ethylene.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Manne, W. Jäger, and J. Tulip "Pulsed quantum cascade laser based cavity ring-down and cavity enhanced spectroscopy for the detection of ethylene.", Proc. SPIE 7099, Photonics North 2008, 709922 (12 August 2008); https://doi.org/10.1117/12.804794
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