Nonlinear interaction of CO2 laser radiation with aluminum and polyethylene targets

The characteristics of A1 and (CH₂)_n plasmas produced by a high-power CO₂ laser are investigated over the flux range 10¹⁰-5 × 10¹¹W/cm² where absorption processes other than simple inverse Bremsstrahlung are active. The threshold dependent behavior of the measured plasma parameters indicates the presence of the parmetric decay instability.