Absolute measurement of gas concentrations and saturation behavior in pulsed photoacoustics

Absolute photoacoustic measurements of the signal strength yielding the concentration and absorption coefficient of ethylene were performed in the IR on the weakly and strongly absorbed 10P10 and 10P14 lines of a pulsed CO2 laser, respectively, using an optimized cylindrical acoustic resonator with Q∼1000. The calculated photoacoustic signal strength agreed with the measured signal within an experimental error of 10%. With the 157 nm radiation of an F2 laser pulsed photoacoustics was extended into the VUV region where photodissociation of C2H4 occurs. Optical saturation phenomena were observed for pulsed CO2 laser and F2 laser excitation below 3 mJ pulse energy.