Mechanism of advanced evaporation of glass under the action of laser radiation

A study was made of the mechanism of the advanced evaporation of K8 glass under the action of optical laser radiation. An increase in the absorption in the surface layer of the transparent glass was due to the photoionization caused by the ultraviolet radiation emitted by the vaporized substance. The gasdynamic parameters of a jet of the evaporated material were deduced from experimental measurements of the recoil impulse and the vapor temperature was calculated approximately for one-dimensional expansion of a gas heated by the incident laser radiation. In the investigated range of power densities the calculated rate of evaporation of the glass agreed to with ~30% with the experimental value.