Method for calibration-free scanned-wavelength modulation spectroscopy for gas sensing

Patent · Tue Apr 10 04:00:00 EDT 2018

OSTI ID:1434512

Hanson, Ronald K.; Jeffries, Jay B.; Sun, Kai; Sur, Ritobrata; Chao, Xing

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

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