Simulation of Laser Ablation in Aluminum: The Effectivity of Double Pulses

TL;DR

This study models laser ablation of aluminum using a two-temperature approach, revealing that double Gaussian pulses with specific delays optimize ablation efficiency, aligning with experimental observations.

Contribution

It introduces a combined heat conduction and molecular dynamics model to analyze the effects of double laser pulses on aluminum ablation.

Findings

Optimal ablation occurs with standard Gaussian pulses.

Ablation depth decreases with delays beyond 10 ps.

Model results align with experimental data.

Abstract

Lasers are becoming a more and more important tool in cutting and shaping materials. Improving precision and effectivity is an ongoing demand in science and industry. One possibility are double pulses. Here we study laser ablation of aluminum by the two-temperature model. There the laser is modeled as a source in a continuum heat conduction equation for the electrons, whose temperature then is transferred to a molecular dynamics particle model by an electron-phonon coupling term. The melting and ablation effectivity is investigated depending on the relative intensity and the time delay between two Gaussian shaped laser pulses. It turns out that at least for aluminum the optimal pulse shapes are standard Gaussian pulses. For double pulses with delay times up to 200 ps we find a behavior as observed in experiment: the ablation depth decreases beyond a delay of 10 ps even if one does not account for the weakening at the second pulse due to laser-plasma interaction.