Fig. 1. Schematic diagram of the super-resolution processing principle and characteristics after processing^[4]. Figure reproduced with permission from ref. [4] © Springer Nature

Fig. 2. Femtosecond laser direct writing^[45]. Figure reproduced with permission from ref. [45] © De Gruyter

Fig. 3. Schematic diagram of the femtosecond laser fabrication based on diffractive optical elements and characteristics after processing^[49]. Figure reproduced with permission from ref. [49] © Springer Nature

Fig. 4. The schematic diagram of the digital micromirror projection system based on femtosecond laser two-photon polymerization and spatio-temporal focusing and characteristics after processing^[57]. Figure reproduced with permission from ref. [57] © The American Association for the Advancement of Science(AAAS)

Fig. 5. Parallel processing based on spatial light modulator. (a) Helical scanning of femtosecond ring-shaped vortex beam based on spatial light modulator^[65]; (b) Generation of Mathieu beam based on spatial light modulator^[66]; (c) Fabrication of microtubes using C-shaped Bessel beam generated by spatial light modulator^[68]. Figure reproduced with permission from: (a) ref. [65] © Wiley; (b) ref. [66] and (c) ref. [68] © American Chemical Society.

Fig. 6. Focal field engineering based on spatial light modulator^[72]. Figure reproduced with permission from ref. [72] © John Wiley and Sons

Fig. 7. Schematic diagram of the femtosecond (fs) laser interference processing and characteristics after processing^[79]. Figure reproduced with permission from ref. [79] © MDPI

Fig. 8. Processing of microlenses. (a) Transferring^[83]; (b) Wet etching^[84]; (c) Dry etching^[86]. Figure reproduced with permission from: (a) ref. [83], (b) ref. [84] and (c) ref. [86] © Wiley

Fig. 9. Micromachining of microlenses based on two-photon polymerization of femtosecond laser. (a) Protein-based microlens in response to the change of pH^[93]; (b) Double-material compound eye in response to the change of pH^[25]. Figure reproduced with permission from: (a) ref. [93] and (b) ref. [25] © Wiley

Fig. 10. Innovative microlenses. (a) Complex microlens arrays based on laser-induced thermal deformation^[95]; (b) Direct patterning of polymeric microlenses based on the combination of femtosecond laser and surface tension of droplet^[96]; (c) Integration of compound lens on the surface of CMOS image sensor based on femtosecond laser^[82]. Figure reproduced with permission from: (a) ref.[95] © Springer Nature; (b) ref. [96] © American Chemical Society; (c) ref. [82] © The American Association for the Advancement of Science (AAAS)

Fig. 11. Femtosecond laser direct writing optical waveguide. (a) Single-line waveguide^[100]; (b) Double-line waveguide^[106]; (c) Depressed cladding waveguide^[111]. Figure reproduced with permission from: (a) ref. [100] and (c) ref. [111] © Wiley; (b) ref. [106] © MDPI.

Fig. 12. Fabrication of micro-gratings based on femtosecond laser. (a) Procedures of femtosecond laser fabricating FBG^[117]; (b) Fabrication of LIPSS on Si substrate utilizing cylindrical lens based on femt osecond laser^[129]; (c) Fabrication of continuous phase vortex grating based on two-photon polymerization of femtosecond laser^[22]. Figure reproduced with permission from: (a) ref. [117] © American Chemical Society; (b) ref. [129] © Wiley; (c) ref. [22] © AIP Publishing

Fig. 13. Fabrication of woodpile photonic crystal whose stop band lies in the visible spectrum based on femtosecond laser^[146]. Figure reproduced with permission from ref. [146] © Springer Nature

Fig. 14. Fabrication of nonlinear photonic crystal based on femtosecond laser. (a) Fabrication of nonlinear photonic crystal in LiNbO₃^[150]; (b) Fabrication of nonlinear photonic crystal in BCT^[151]. Figure reproduced with permission from: (a) ref. [150] and (b) ref. [151] © Springer Nature