Effects of laser radiation on materials in an argon atmosphere over a wide range of pressures
Experimental data are given on the effects of radiation from a pulsed neodymium laser (τ≈1 msec) on materials (metals, dielectrics, semiconductors) in an argon atmosphere with the pressure varying in the range 1–130 atm and the radiation power density q = 106–107 W/cm2. In the argon atmosphere, as in the experiments in nitrogen at elevated pressures, a plasma cloud formed near the target surface, screening the interaction zone from the direct incidence of the focused radiation on the target. The parameters and evolution characteristics (from the appearance to recombination) of the resultant plasma cloud were a function of the radiation power density, the gas pressure, and the physical properties of the targets. The characteristics of the interaction between the radiation and the materials at high argon pressures (compared with normal conditions) were associated with the partial absorption of the laser radiation in the plasma and refraction of the beam. The changes in the characteristics of the target surface caused by the joint action of the laser radiation and the plasma radiation are discussed.