Method for calibration-free scanned-wavelength modulation spectroscopy for gas sensing
A method of calibration-free scanned-wavelength modulation spectroscopy (WMS) absorption sensing is provided by obtaining absorption lineshape measurements of a gas sample on a sensor using 1f-normalized WMS-2f where an injection current to an injection current-tunable diode laser (TDL) is modulated at a frequency f, where a wavelength modulation and an intensity modulation of the TDL are simultaneously generated, extracting using a numerical lock-in program and a low-pass filter appropriate band-width WMS-nf (n=1, 2, . . . ) signals, where the WMS-nf signals are harmonics of the f, determining a physical property of the gas sample according to ratios of the WMS-nf signals, determining the zero-absorption background using scanned-wavelength WMS, and determining non-absorption losses using at least two of the harmonics, where a need for a non-absorption baseline measurement is removed from measurements in environments where collision broadening has blended transition linewidths, where calibration free WMS measurements without knowledge of the transition linewidth is enabled.
- Research Organization:
- The Board of Trustees of the Leland Stanford Junior University, Palo Alto, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FE0001180
- Assignee:
- The Board of Trustees of the Leland Stanford Junior University (Palo Alto, CA)
- Patent Number(s):
- 9,939,376
- Application Number:
- 14/367,420
- OSTI ID:
- 1434512
- Country of Publication:
- United States
- Language:
- English
Calibration-free wavelength-modulation spectroscopy for measurements of gas temperature and concentration in harsh environments
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journal | January 2009 |
Dependence of harmonic signals on sample-gas parameters in wavelength-modulation spectroscopy for precise absorption measurements
|
journal | October 1998 |
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