Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7225075 | Optik - International Journal for Light and Electron Optics | 2018 | 5 Pages |
Abstract
Laser intracavity photoacoustic spectroscopy (ICPAS), in combination laser intracavity absorption (ICAS) with photoacoustic spectroscopy(PAS) technology is presented. It can effectively enhance the photoacoustic signal intensity by means of increasing the laser power and overlapping in phase when the laser beam passed through the acoustic wave detector every time. Two sets of experimental results were obtained when probing the water vapor with the effective absorption coefficient, keff, 1.06Â ÃÂ 10â6cmâ1Â ÃÂ ppmâ1 in the air using a tunable distributed feedback laser diode (DFB-LD) and validate the relevance of the reported mathematical model. It can be found that for a quartz-enhanced photoacoustic spectroscopy(QEPAS) sensor system, the relationship between the second harmonic current amplitude I2f and the laser power WL is linear, and the slope of the fitting results is 285.0809Â pA/mW compared to that of theoretical calculation 278.7025Â pA/mW, with the fitting constant of 17.1318âpA, which was corresponding to the laser power less than 0.0601âmW and for a resonant photoacoustic(PA) cell sensor system, the relationship between the second harmonic voltage amplitude U2f and the laser power WL is also linear, and the slope of the fitting results is 108.8463Â mV/mW compared to that of theoretical calculation 111.26Â mV/mW, with the fitting constant of 0.4875Â mV, which was corresponding to the laser power less than 0.0045âmW.
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Authors
Aiping Li, Jun. Chang, Yongning Liu, Qiang Wang, Zongliang Wang,