Fig. 1. Comparison of laser beam propagation intensity in focal region^[22]. (a) Before improvement; (b) after improvement

Fig. 2. Simulated 3D ablation craters by single pulses with different laser intensities^[41]. (a) 2 J/cm²; (b) 5 J/cm²; (c) 8 J/cm²

Fig. 3. Snapshot of ablation plume, and obvious differences in plume structure^[42]

Fig. 4. Ablation mechanism changes with material depth and laser intensity^[43]

Fig. 5. Spatial and temporal distributions of phase states of different ablation metals with HD method. (a) Copper^[45]; (b) aluminum^[34]; (c) nickel^[44]; (d) gold^[46]

Fig. 6. Relationship between ablation depth of aluminum and laser fluence(comparison between experimental data and HD simulation data)^[48]

Fig. 7. Pressure and density near spallation threshold F_s=193 mJ/cm^2[49]. (a) Pressure; (b) density

Fig. 8. Calculated total laser absorption by plume as a function of laser intensity^[56]

Fig. 9. Absorption of the first (blue squares) and the second (red circles) pulses by plasma plumes as a function of delay between them. Intensity of each pulse is 2 J/cm^2[57]

Fig. 10. Simulation results obtained for linear polarization with intensity of 10¹⁰ W/cm² after 10 fs^[69].(a) Electronic density profile; (b) electrical field profile

Fig. 11. Simulation results obtained for circular polarization with intensity of 10¹⁰ W/cm² after 10 fs^[69].(a) Electronic density profile; (b) electrical field profile

Fig. 12. Formation of liquid walls during ablation^[73]

Fig. 13. Schematics of electromagnetic and hydrodynamic coupling processes upon multipulse femtosecond laser irradiation^[74]