The role of multi-photon dissociation of high pressure SF6 gas in TEA CO2 lasers pulse shaping

High pressure SF6 gas has been irradiated by intense TEA CO2 laser pulses with different wavelengths around 10.6 mu m and then, temporal variations of the transmitted laser pulses have been characterized at different energy fluences and gas pressures. It has been shown that for every fluence above the multi-photon dissociation threshold of SF6 molecules, there is a certain cut-off pressure at which the pulse spike is completely quenched. While, the pulse tail escapes with an appreciable fraction of its initial energy. FTIR spectra of the irradiated gases together with other experimental evidences have clearly revealed the occurrence of laser induced multi -photon dissociation of SF6 molecules, that should be considered as the main responsible for the observed pulse shaping effects.