First-Principles Calculations Exploring Initial Stage of Laser Processing

Abstract

We develop a first-principles computational approach for dynamics of electrons and optical fields in crystalline solids that will be useful to explore initial stages of nonthermal laser processing of dielectrics. In the method, we describe atomic-scale electron dynamics in dielectrics induced by an intense and ultrashort laser pulse based on time-dependent density functional theory. Combining the electron dynamics calculation with Maxwell equations that describe propagation of the laser pulse, we evaluate the energy transfer from the laser pulse to electrons in the dielectrics without any empirical parameters. Comparing the energy transfer with the cohesive energy and the heat of fusion of the dielectrics, we estimate threshold and depth of laser ablation.