Simultaneous detection of multiple gases using multi-resonance photoacoustic spectroscopy

In this paper, a gas sensing technique based on multi-resonance photoacoustic spectroscopy (M-PAS) is firstly proposed for simultaneous detection of multi-component gas molecules. To explore the capabilities of this technique, a spherical resonator with multiple resonant modes and high quality factors are detailedly developed by theoretical simulation and experimental analysis. The proposed M-PAS technique combing with wavelength modulation spectroscopy (WMS) is investigated for simultaneous detection of H2O, CO2 and CH4, respectively(.) Based on Allan-Werle deviation analysis, the detection limits of 1.17 ppm for H2O, 83 ppm for CO2 and 1.76 ppm for CH4, respectively, at the integration time of 136 s, 181 s and 195 s were achieved, corresponding to the normalized noise equivalent absorption (NNEA) coefficient of 6.03 x 10(-10) cm(-1)W/root Hz, 5.46 x 10(-10) cm(-1)W/root Hz, 2.36 x 10(-9) cm(-1)W/root Hz. The reported sensing technique has potential applications in atmospheric environment monitoring, industrial process control and breath gas analysis by appropriate improvements, and can easily be modified for other multi-component gas analysis.