Paper
23 September 2002 Sensitive absorption measurements in the near-infrared region using off-axis integrated cavity output spectroscopy
Douglas S. Baer, Joshua B. Paul, Manish Gupta, Anthony O'Keefe
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Abstract
A novel instrument that employs a high-finesse optical cavity as an absorption cell has been developed for sensitive measurements of gas mixing ratios using near-infrared diode lasers and absorption spectroscopy techniques. The instrument employs an off-axis trajectory of the laser beam through the cell to yield an effective optical path length of several kilometers without significant unwanted effects due to cavity resonances. As a result, a minimum detectable absorption of ~1.4x10-5 over an effective optical path of 4,200 meters was obtained in a 1.1-Hz detection bandwidth to yield a detection sensitivity of ~3.1x10-11 cm-1 Hz-1/2. The instrument has been applied for measurements of CO, CH4, C2H2, and NH3 in the 1530-1650 nm range, and stable isotopes of CO2 (13CO2, 12CO2, 12C16O18O) near 2052 nm.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Douglas S. Baer, Joshua B. Paul, Manish Gupta, and Anthony O'Keefe "Sensitive absorption measurements in the near-infrared region using off-axis integrated cavity output spectroscopy", Proc. SPIE 4817, Diode Lasers and Applications in Atmospheric Sensing, (23 September 2002); https://doi.org/10.1117/12.451461
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CITATIONS
Cited by 19 scholarly publications and 27 patents.
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KEYWORDS
Absorption

Carbon monoxide

Semiconductor lasers

Mirrors

Gas lasers

Spectroscopy

Temperature metrology

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