Paper
10 January 1997 Modulation spectroscopy with diode lasers: applications in spectroscopy and nonintrusive measurements
Amin N. Dharamsi, Audra Michelle Bullock
Author Affiliations +
Abstract
Theoretical and experimental results related to wavelength modulation absorption spectroscopy using single-mode diode lasers are presented. This method uses a phase-sensitive detection technique, and the implications of detection at harmonics greater than the commonly used second-harmonic are discussed. It is shown that several advantages accrue with such higher-harmonic detection. Applications of the method in increasing sensitivity to measurements of density and temperature fluctuations; in increasing wavelength resolution of modulation and pressure broadened congested spectra; and in applications for accurate characterization of absorption lines of molecular spectra, are discussed. It is shown that wing structure of absorption lines can be obtained with much more accuracy using higher harmonic detection than either direct absorption or the commonly used second harmonic detection technique. Experimental results obtained are compared to the predictions of the theory developed.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Amin N. Dharamsi and Audra Michelle Bullock "Modulation spectroscopy with diode lasers: applications in spectroscopy and nonintrusive measurements", Proc. SPIE 3000, Laser Diode and LED Applications III, (10 January 1997); https://doi.org/10.1117/12.263483
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KEYWORDS
Modulation

Signal detection

Absorption

Spectroscopy

Laser spectroscopy

Semiconductor lasers

Temperature metrology

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