Ablation of gold irradiated by femtosecond laser pulse: Experiment and modeling

31st International Conference on Equations of State for Matter

Ashitkov, S.I.^1 ; Komarov, P.S.^1 ; Zhakhovsky, V.V.^1,2,3 ; Petrov, Yu V^3 ; Khokhlov, V.A.^3 ; Yurkevich, A.A.^1 ; Ilnitsky, D.K.^2,3 ; Inogamov, N.A.^3 ; Agranat, M.B.^1

Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13, Moscow

125412, Russia^1

Dukhov Research Institute of Automatics (VNIIA), Sushchevskaya 22, Moscow

127055, Russia^2

Landau Institute for Theoretical Physics, Russian Academy of Scienses, Akademika Semenova 1a, Chernogolovka, Moscow Region

142432, Russia^3

关键词: Ablation thresholds;    Electron ions;    Heated surfaces;    Liquid layer;    Molecular dynamics methods;    Sub nanoseconds;    Thermalization;    Thin surface layer;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/774/1/012097/pdf
DOI  :  10.1088/1742-6596/774/1/012097

来源: IOP

【 摘 要 】

We report on the ablation phenomena in gold sample irradiated by femtosecond laser pulses of moderate intensity. Dynamics of optical constants and expansion of a heated surface layer was investigated in a range from picosecond up to subnanosecond using ultrafast interferometry. Also morphology of the ablation craters and value of an ablation threshold (for absorbed fluence) were measured. The experimental data are compared with simulations of mass flows obtained by two-temperature hydrodynamics and molecular dynamics methods. Simulation shows evolution of a thin surface layer pressurized by a laser pulse. Unloading of the pressurized layer proceeds together with electron-ion thermalization, melting, cavitation and spallation of a part of surface liquid layer. The experimental and simulation results on two-temperature physics and on a fracture, surface morphology and strength of liquid gold at a strain rate ∼ 109s-1are discussed.