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A wavelength-locked laser gaseous species monitor including a variable wavelength laser with a laser output actively stabilized to a wavelength at or near an absorption wavelength of the species being monitored. The laser is modulated about that wavelength to establish a modulated output with a know

A wavelength-locked laser gaseous species monitor including a variable wavelength laser with a laser output actively stabilized to a wavelength at or near an absorption wavelength of the species being monitored. The laser is modulated about that wavelength to establish a modulated output with a known frequency and bandwidth. The modulated output is passed through the sample being monitored and then collected. An even harmonic of the collected output with respect to the modulation frequency is determined, and the presence in the sample of the species being monitored is detected from the even harmonic signal.

대표청구항 ▼

A wavelength-locked laser gaseous species monitor, comprising: variable wavelength laser means for providing a laser output; means for adjusting the central wavelength of said laser output to a first laser wavelength at or near a first absorption wavelength of a species being monitored; means for mo

A wavelength-locked laser gaseous species monitor, comprising: variable wavelength laser means for providing a laser output; means for adjusting the central wavelength of said laser output to a first laser wavelength at or near a first absorption wavelength of a species being monitored; means for modulating said laser output about said first laser wavelength to establish a first modulated output having a first modulation frequency and a first modulation bandwidth and a second modulated output having said first modulation frequency and a second modulation bandwidth; means for providing said first and second modulated outputs to a sample being monitored; means for collecting at least some of said modulated outputs transmitted through said sample; means for determining an even harmonic of the collected outputs with respect to said first modulation frequency; means, responsive to said means for determining, for detecting from said even harmonic of said fist or said second modulated outputs the presence in said sample of said species being monitored; and means for resolving the concentration of the species being monitored by comparing said even harmonics of said collected outputs.