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Gas spectroscopy

  • US 5,491,341 A
  • Filed: 04/15/1994
  • Issued: 02/13/1996
  • Est. Priority Date: 04/16/1993
  • Status: Expired due to Term
First Claim
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1. A method, comprising:

  • generating laser radiation with a laser diode and passing said laser radiation through a sample gas;

    obtaining a first value indicative of a peak absorption of said laser radiation by said sample gas substantially at a peak of an absorption line of said sample gas;

    obtaining a second value indicative of a line width of said absorption line; and

    using said values indicative of said peak absorption and said line width to determine a third value indicative of a number of molecules of said sample gas through which said laser radiation passes, said third value being substantially independent of line-broadening effects,wherein said generating comprises supplying said laser diode with a driving current, said driving current having a periodic waveform comprising a plurality of constant current intervals, a first, a second and a third of said constant current intervals causing said laser diode to emit laser radiation at first, second and third wavelengths respectively, said first wavelength being smaller than said second wavelength, said third wavelength being greater than said second wavelength, said second wavelength corresponding with the peak of said absorption line, the first and third wavelengths corresponding with locations on said absorption line having substantially identical absorptions.

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