Intensive evaporation of germanium and silicon by millisecond laser radiation pulses

An experimental investigation was made of the intensive evaporation of germanium and silicon by laser pulses of I ≈ 10⁶–10⁷ W/cm² intensity. The specific recoil momentum and ejected mass, and the depth of the crater in a target were determined as a function of the radiation intensity. The reflection coefficient was determined as a function of I. The experimental results indicated that the behavior of these two materials under the action of high-power optical radiation was similar to the behavior of metals. The experimental results were in satisfactory agreement with the theory of intensive evaporation of metals based on the assumption that the process involved the liquid–vapor phase transition.