The optoacoustic technique is used to measure the absorption of CO2 TEA laser energy in SF6 as a function of frequency and energy flux at 293 and 145 K. The behavior of absorbed-energy versus incident-energy flux curves shows a strong dependence on frequency-at 145 K, whereas at 293 K the dependence is less pronounced. When the CO2 pulse is lengthened sufficiently, laser-induced hot-band effects arising from vibrational relaxation during the pump pulse can be observed.
T. F. Deutsch, "Optoacoustic measurements of energy absorption in CO2 TEA-laser-excited SF6 at 293 and 145 K," Opt. Lett. 1, 25-27 (1977)