Fig. 1. SEM images of self-organized nano-gratings in the transversal cross section of written lines^[42]

Fig. 2. SEM images of various designed suspended structures (line, disk, helix, and pentagon stuctures)^[43]

Fig. 3. Complicated 3D structures^[44]. (a) Three-level steps; (b) the word “LASER” on a rectangular step; (c) rectangular pyramid; (d) concave micro lens array

Fig. 4. Bubbles induced at different FDs^[9]

Fig. 5. Cross section of optical waveguide fabricated in Nd∶KGW^[49]. A is the waveguide area, B is the filament induced by the femtosecond laser, and C is the unprocessed area (bulk) far away from the filament

Fig. 6. Femtosecond laser inscription of optical waveguide in SMF-NCF-SMF^[50]

Fig. 7. Experimental setup for fabrication of ULPFBGs^[51]

Fig. 8. Fabricated grating structure in the core of fiber^[51]

Fig. 9. Microscope images of cross section of sapphire fiber and inscribed fourth-order SFBG^[38]. (a) Microscope image of cross section of sapphire fiber with diameter of 60 μm; microscope images of inscribed fourth-order SFBG: (b) top view and (c) side view

Fig. 10. Schematic diagram of line-by-line scanning method^[6]

Fig. 11. Photomicrographs of fabricated SFBG^[6]. (a) Top view; (b) side view

Fig. 12. Four in-fiber mirrors^[52]

Fig. 13. Same micro-structures made by different scanning methods^[55]. (a) Raster mode; (b) vector mode

Fig. 14. Polymer waveguide integrated in the fibre micro-cavity^[32]. (a) Top view of fabricated polymer waveguide integrated in fiber micro-cavity; (b) polymer waveguide with length of 60 μm; (c) polymer waveguide with length of 80 μm

Fig. 15. Fabrication process diagram of liquid polymer filled-cavity FP fiber sensing structure^[33]

Fig. 16. Optical microscope images of polymerized grating^[58]. (a) Before rinsing; (b) after rinsing

Fig. 17. Microstructure of spiral channels in glass^[8]. (a) Diagram of spiral-shaped microchannel; (b) side view of etched spiral-shaped microchannel by HF acid inside glass; (c) side view of spiral-shaped microchannel after baking of etched sample at 600 ℃ for 4 h; (d) cross-section of post baked microchannel; (e) cross-section of channel at the opening area

Fig. 18. Side view of blue solution flowing through spiral-microchannel^[8]

Fig. 19. Helical microchannel in quartz glass^[71]. (a) Fabricated helical microchannel with block at end of channel; (b)(c) fabricated helical micro channels with length of 1 mm

Fig. 20. Structures of micro diverter and micro mixer^[72]. (a) Empty micro mixer; (b) micro mixer filled with water; (c) empty micro diverter; (d) micro diverter filled with water

Fig. 21. Three-dimensional microfluidic chip^[73]. (a) Diagram of microfluidic chip; (b) fabricated microfluidic chip in silica glass

Fig. 22. Fabricate micro channels in optic fibers using femtosecond laser-induced water break down^[74]

Fig. 23. Structures of liquid refractive index sensor with three micro channels across fiber core^[72]. (a) Front view; (b) top view; (c) opening of microchannel on the top of fiber; (d) opening of microchannel on the bottom of fiber

Fig. 24. H-type humidity sensor in SMF^[76]. (a) Top view of fabricated two vertical micro channels rightly across fiber core; (b) side view of fabricated two vertical micro channels rightly across fiber core in SMF in the first step; (c) top view of fabricated H-type microchannel in SMF; (d) side view of fabricated H-type microchannel in SMF

Fig. 25. MZ interferometer microcavity in SMS fiber structure by femtosecond laser-induced water breakdown^[78]. (a) A section of multi mode fiber was spliced between two sections of the SMF; (b) structure of SMS; (c) setup for fabricating microcavity in SMS by femtosecond laser-induced water breakdown; (d) scanning track of laser focus; (e) fabricated microcavity in SMS