Fig. 1. Schematic diagram of femtosecond laser etching quartz glass grating

Fig. 2. Schematic diagram of laser etching method.(a) CAD drawing of femtosecond laser etching path (gratings); (b) method of top-down femtosecond laser processing

Fig. 3. Effects of laser power on etching width and edching depth. (a) Etching width; (b) etching depth

Fig. 4. Effects of scanning velocity on etching width and etching depth. (a) Etching width; (b) etching depth

Fig. 5. Effects of repeated scanning layers on etching width and etching depth. (a) Etching width; (b) etching depth

Fig. 6. Typical etched grating. (a) Microscope image of etched grating; (b) three-dimensional confocal microscope colour morphology image of etched grating

Fig. 7. Experimental setup for measuring diffraction efficiency of quartz glass grating

Fig. 8. Spot recorded by CCD. (a) Original spot without grating; (b) diffraction spot with grating (-1st, 0th and +1st)