Two-phase mechanism of laser-induced removal of thin absorbing films. I. Theory

Abstract

A physical model of laser-induced removal of thin absorbing films is proposed. The qualitative concepts of melt surface evaporation and of melt motion under the action of the reactive vapour pressure, of surface tension forces and of adhesion, support the model. The basic equations describing the removal process are solved numerically. An analytical parameter phi , characterising the relationship between the liquid and vapour phases of the removed material, is obtained. It is shown that, depending on the direction of the inequality phi <<1 or phi >>1, evaporation or liquid phase motion respectively plays the principle role in the film removal mechanism.