Ablation study in gold irradiated by single femtosecond laser pulse with electron temperature dependent interatomic potential and electron-phonon coupling factor

• Published in: Laser physics Vol. 31; no. 3; pp. 36002 - 36011
• Main Authors: Yuan, Weirong, Sizyuk, Tatyana
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.03.2021
• Subjects: ablation; atomistic-continuum model; femtosecond laser; melting; phase explosion; spallation; temperature dependent interatomic potential
• ISSN: 1054-660X; 1555-6611
• DOI: 10.1088/1555-6611/abdcb8

The interactions of femtosecond lasers with gold targets are investigated with a numerical method combining molecular dynamics and two-temperature model and temperature dependent thermodynamic parameters. The influence of the electron temperature dependent (ETD) interatomic potential on ablation processes was analyzed. We also adopted an ETD electron-phonon coupling factor and further analyzed different ablation mechanisms under absorbed fluences ranging from 40mJcm−2to150mJcm−2. Our simulation results showed good agreements on melting and ablation depth with both experiments and other simulations. Three ablation mechanisms were identified: nonthermal ablation caused by electronic pressure from the ETD interatomic potential, spallation by stresses from a rapid heating of the target and phase explosion due to explosive boiling. With a continuously updated ETD potential in accordance with electron temperature, one can explain the unique U shape profile of plume atomization degree as a function of laser fluence found in experiments.