Influence of the ambient air pressure on short-wavelength radiation from a laser plasma

A detailed experimental investigation was made of the radiation from a plasma created on an aluminum target by a pulsed CO₂ laser at different ambient gas pressures. Measurements were made of the energy and angular distribution of the radiation and of the efficiency of conversion of laser energy into reemitted plasma radiation. The intensity of this radiation was found to exhibit pressure-dependent pulsations. The maximum reflection of the laser radiation from the plasma was recorded at a pressure of ~ 40 Torr. An interpretation is given of the experimental data.