Fig. 1. Overview of applications of laser cutting technology for hard and brittle materials

Fig. 2. Typical optical nonlinear effects. (a) Schematic diagram of the multiphoton absorption process^[10]; (b) schematic diagram of dynamic balance between self focusing effect and plasma defocusing effect during wire transfer process^[11]

Fig. 3. Laser cutting of thick and brittle materials. (a) Through-hole laser non-destructive machining technology ^[14]; (b) diagram of multi-focus processing (left) and cutting of 2 mm sapphire (right)^[19]

Fig. 4. Laser cutting of thick and brittle materials using Bessel laser beam. (a) High depth-to-diameter ratio Bessel beam designed by double axicon design for the realization of 10 nm SiO₂ glass cutting ^[24]; (b) femtosecond Bessel beam shaping and free patterning for cutting SiO₂ glass^[26]

Fig. 5. Ultrafast laser filamentation processing of hard and brittle materials. (a) Comparison of water film assisted laser filamentation method and its processing effects^[28];(b) filamentation effects of picosecond lasers with different energy densities^[29]; (c) large thickness sapphire samples prepared by combining laser filamentation cutting and chemical corrosion method^[30]

Fig. 6. Laser processing of 3D structures on hard and brittle materials. (a) 3D structure of laser milling Al₂O₃ ceramics^[32]; (b) 3D laser milling of gold-plated porcelain^[33]; (c) 3D laser milling of Al₂O₃ ceramic microelectromechanical structural components^[34]; (d) 3D laser processing for forming ceramic free-form surface structures^[35]

Fig. 7. Laser processing of complex multidimensional structures on hard and brittle materials. (a) Laser cutting of ceramic (helical) gear device^[37]; (b) ceramic cutting diagrams before (left) and after (right) laser processing path registration^[38]

Fig. 8. LIPAA applied for the laser cutting of hard and brittle materials^［42］. (a) Schematic diagram of experimental setup for the cutting of sapphire using LIPAA; (b) LIPAA processing high aspect ratio micro groove structures; (c) LIPAA processing microstructure on sapphire surface

Fig. 9. Water assisted laser cutting of hard and brittle materials. (a) Water assisted femtosecond laser drilling and cutting^[45]; (b) water guided laser cutting^[46]

Fig. 10. Chemical etching assisted laser cutting technology. (a) High precision cutting using laser combined with backward chemical etching method^[52]; (b) backward laser combined with forward chemical etching method for high-precision cutting^[53]

Fig. 11. O-FIB laser super-stealth dicing technology for hard and brittle materials^[54]. (a) Diagram of O-FIB effect; (b) high precision laser nano-cutting