Fig. 1. Schematic of direct writing and etching of BF33 glass based on ultraviolet micromachining system

Fig. 2. Physical map of experimental device. (a) All-solid-state ultraviolet laser; (b) processing platform; (c) FPS ultraviolet micromachining system

Fig. 3. Surface morphologies and depths of micro-channels in borosilicate glass by ultraviolet laser etching under different energy densities. (a) 25.28 J·cm-2; (b) 34.55 J·cm-2; (c) 43.70 J·cm-2; (d) 53.23 J·cm-2; (e) 68.84 J·cm-2; (f) micro-channel depth versus laser energy density

Fig. 4. Surface morphologies and depths of micro-channels in borosilicate glass by ultraviolet laser etching under different repetition frequencies. (a) 40 kHz; (b) 30 kHz; (c) 25 kHz; (d) micro-channel depth versus laser repetition frequency

Fig. 5. Surface morphologies and depths of micro-channels in borosilicate glass by ultraviolet laser etching under different scanning speeds. (a) 1.0 mm·s-1; (b) 0.5 mm·s-1; (c) 0.2 mm·s-1; (d) micro-channel depth versus laser scanning speed

Fig. 6. Bottom morphologies of micro-channels in borosilicate glass by ultraviolet laser etching under different scanning distances. (a) 25 μm; (b) 15 μm; (c) 10 μm

Fig. 7. Cross-sectional SEM images and depths/tapers of micro-channels in borosilicate glass by ultraviolet laser etching under different number of scanning. (a) 1 time; (b) 2 times; (c) 3 times; (d) 4 times; (e) micro-channel depth versus number of laser scanning; (f) micro-channel taper versus number of laser scanning

Fig. 8. Overall morphology of L-shaped micro-channel etched under optimal processing parameters

Table 1. Correspondence between laser pulse width and repetition frequency