Fig. 1. Phenomena at different time scales when materials are exposed to ultrashort laser irradiation^[6-7] and the relationship of the contents of this article

Fig. 2. Electron ionization process of dielectric materials when subjected to ultrashort laser action, as described by the time-dependent density functional theory (TDDFT). (a) Influence of laser ellipticity on the generation of higher harmonics in MgO^[20]; (b) effect of pulse trains on the population of excited electrons in quartz^[23]

Fig. 3. Changes in system energy and material properties of metals generated by photons, which is determined using the finite electron-temperature-based density functional theory (DFT) approach. (a) The density of states (DOS) for different metals varying with electronic temperature^[30]; (b) electron heat capacity of various metals varying with electronic temperature^[32]

Fig. 4. Computation of electronic parameters of stainless steel using the finite electron-temperature-based DFT approach^[33]. (a) Crystal structure of stainless steel; (b) electron-phonon coupling coefficient varying with electronic temperature

Fig. 5. Atomic-scale simulation diagram of energy transfer and molecular decomposition process involved in laser irradiation. (a) Mechanism of phototropic phase transitions in monoclinic VO₂^[43]; (b) dynamic process of copper and nickel when subjected to ultrashort laser irradiation^[44]

Fig. 6. Atomic-scale simulation of the solid-state amorphous process of Ge-Sb-Te at the end of laser pulse irradiation^[47]

Fig. 7. Simulation of ultrashort laser material ablation based on electron excitation rate equation^[55]. (a) Evolution of electron density with an increase in laser energy; (b) schematic diagram for determining the critical value for material ablation

Fig. 8. Comparison of electronic temperature and lattice temperature obtained by parameter-uncorrected and modified two-temperature equations^[61]. (a) Parameter-uncorrected two-temperature equation; (b) parameter-modified two-temperature equation

Fig. 9. Simulation of ultrashort laser ablation based on molecular dynamics^[83]. (a) Particle diffusion graphs at various laser energies; (b) evolution of HMX at atomic scales

Fig. 10. Theoretical model that integrates molecular dynamics with two-temperature equation^[85]. (a) Schematic diagram of calculation method of coupled molecular dynamics with two-temperature equation; (b) amalgamation of many simulation regions into a single pulse laser ablation pattern

Fig. 11. Electron-phonon coupling coefficient of Au film deduced theoretically varying with electron temperature^[93]

Fig. 12. Simulation of the formation process of laser-induced periodic nano-ripple structures on metal surface. (a) Effect of laser energy and pulse number on the formation process of nano-ripples on stainless steel surface^[95]; (b) formation process of high and low spatial-frequency nano-ripples on nickel metal surface^[96]

Fig. 13. Simulation of the generation of nano‑ripple structures on the surface of dielectric materials. (a) Formation of nano‑ripple structures and microstructures on silicon surface at pulse number of 60^[97]; (b) evolution of silica internal structure with pulse number and formation of nano‑ripple structures^[99]