Self-focusing of 10-microm laser pulses in SF(6)

Self-focusing and self-defocusing of 1.6-nsec CO(2) laser pulses were observed in SF(6) gas for several selected 10-microm P-branch lines. The lines P(8), P(10), P(14), and P(16) self-focused, P(28) defocused, and either effect occurred at P(20), depending on the incident energy. The self-focusing was found to depend on incident fluence rather than on intensity and weakly on He buffer. Under the appropriate conditions beam filamentation occurred.