Fig. 1. SEM images of holes drilled in a 100 μm thick steel foil with laser pulses of (a) 200 fs and (b) 3.3 ns, respectively^[10]

Fig. 2. (a) Single photon absorption and (b) multiphoton absorption based on electron excitation processes in bandgap materials^[13]

Fig. 3. Schematic of femtosecond laser direct writing system^[22]

Fig. 4. (a) Schematic illustration of dual-3D femtosecond laser direct writing processing; (b) Design and fabrication of a microflower by dual-3D femtosecond laser processing^[5]

Fig. 5. (a) Schematic diagram of an SLM-based fabrication system; (b) Microcage structure prepared using the fabrication system in (a)^[40]

Fig. 6. (a) Varifocal compound eye^[6]; (b) Schematic diagram of fabrication of sapphire concave compound eye template and K9 glass compound eye^[7]

Fig. 7. PMMA 3D microchannels prepared by femtosecond laser^[71]

Fig. 8. (a) LIPSS structure prepared by femtosecond laser on Cu foil; (b) Structured graphene film grown on the laser-structured Cu foil^[8]