Nonresonant interaction of high-power optical radiation with a liquid

Various aspects of the problem of nonresonant interaction of high-power optical radiation with a liquid are discussed. The nonlinear response of the liquid to a pulse of radiation that significantly affects the thermodynamic state of the liquid (in particular, transforms the liquid into the vicinity of the critical point) is described. Specific features of boiling of the liquid under the action of the laser radiation are pointed out. The instability of the planar vaporization front, arising from the action of radiation on the free surface of an absorbing liquid, with respect to small spatiall perturbations of the phase separation boundaries and the perturbations of the temperature distribution related to them are analyzed. The generation of sound pulses and monochromatic sound waves in the liquid, as a result of the action of laser radiation, and their transformation with subsequent propagation are described. The efficiency of “thermal” and “striction” mechanisms for photoexcitation of sound are compared. The phenomenon of deep melting penetration (dagger-shaped penetration zone) of metals under the action of laser radiation, related to the presence of a liquid phase (metallic melt) in the interaction zone, is discussed. The resullts of studies concerning the interaction of high-power light fluxes with metallic targets are presented. It follows from these results that within a well-defined range of laser radiation intensities a metal-dielectric transition occurs in the interaction zone, but the appearance of the dielectric phase has no qualitative effect on the nature of the interaction.