Theoretical determination of the effective duration of evaporation under nanosecond laser ablation

A theoretical study of the effect of temporary non-uniformity of the surface temperature on the duration of evaporation during nanosecond laser ablation has been performed. Calculations based on the thermal model of laser ablation for a wide range of materials have been carried out. A universal dependence of the effective duration of evaporation on the surface temperature has been obtained. Analytical formulas have been derived that determine the effective duration of evaporation and the average value of the evaporating surface temperature for the Gaussian distribution of the absorbed laser radiation. It is shown that the analytical dependences are in good agreement with the results of numerical calculations. The obtained data are important for determination of initial conditions for theoretical analysis of the gas-dynamic stage of laser ablation.