An acoustically resonant CO2 laser photoacoustic (PA) spectrometer for remote or in situ monitoring of air pollutants has been designed. The salient features of this PA system, along with the optimization tests of various operating parameters that affect the PA signal (buffer-gas pressure, type of buffer gas, laser power, gas concentration, and acoustic modes), are described. The system has been applied for the detection of pollutants emitted from the exhaust of a car located at a remote distance. Also, an alarm system based on the PA detection technique has been built for leak detection of toxic gases at industrial complexes. The minimum detectable concentration of C2 H4 and SO2 with this system is 50 parts in 1012 by volume and 50 parts in 109 by volume, respectively.
© 1997 Optical Society of America
M. A. Gondal, "Laser photoacoustic spectrometer for remote monitoring of atmospheric pollutants," Appl. Opt. 36, 3195-3201 (1997)