Ejection of atoms by laser produced optical breakdown plasma

High-power CO₂ laser radiation has been used to study the optical breakdown plasma on various solid targets (NaCl, KBr, ZnSe, and Ge). The breakdown threshold for irreversible changes of the optical characteristics was determined as well as the evaporation threshold of Na atoms from NaCl samples by CO₂ laser irradiation; the latter value was about 2.8×10⁷ W/cm². The time profiles of the ejected Na atoms and the propagation of the atoms in front of the sample was measured with the laser fluorescence method.