Method for obtaining gas concentration with a phase-based metrology system.
A new technique is presented for obtaining gas concentration by measuring the slope of the anomalous dispersion at a resonance. We describe the equations that govern this process using a Lorentz model and show that the slope of the anomalous dispersion is directly related to the absorption coefficient. The slope is obtained from an interferometric setup and a frequency modulation spectroscopy technique. Experimental data are presented that illustrate this technique for two different sample cells containing water vapor.
Schwarze
C R
CR
Gargas
J A
JA
Rentz
J H
JH
Hercher
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M