Fig. 1. Optical path device diagram of femtosecond laser spatial-shaping based on SLM

Fig. 2. Simulation diagram of rectangular flat-top beam and grayscale image. (a) Simulation diagram of a rectangular spot; (b) grayscale image obtained by an iterative algorithm

Fig. 3. Characterization of light spot and pulse dot after shaping. (a) Light spot distribution of rectangular flat-top light measured by a beam quality profiler; (b) morphological image of surface with 20 pulses flat-top light ablation; (c) morphological image of surface with 100 pulses flat-top light ablation; (d) morphological image of surface with 500 pulses flat-top light ablation

Fig. 4. Comparison of microgroove array processed by Gaussian beam and flat-top beam. (a) SEM image of microgroove array fabricated by Gaussian beam; (b) SEM image of microgroove array fabricated by flat-top beam; (c) cross-sectional profile of a single microgroove (100 scanning times) fabricated by Gaussian beam; (d) cross-sectional profile of a single microgroove (100 scanning times) fabricated by flat-top beam; (e) relationship between the depth and the slope of the microgroove arrays

Fig. 5. Comparison of microgrooves fabricated by flat-top beam at different scanning speeds

Fig. 6. Variation of depth and slope of microgrooves under different pulse energies. (a) Depth of microgrooves changed with scanning times; (b) slope of microgrooves changed with microgroove depth and scanning times

Fig. 7. Microgroove arrays with variable width processed by spatially shaped beam. (a) Surface morphology of the microgroove array; (b) cross-sectional profile of microgroove array

Fig. 8. Topographies of microgrooves with width of 10μm and 20μm

Fig. 9. Topography of microgroove with width of 150μm. (a) SEM image; (b) three-dimensional white light interference image; (c) cross-sectional profile view

Fig. 10. Distribution and intensity changes of elements at the processing edge of microgroove. (a) SEM image of the microgroove side wall section; (b) transverse distribution of element intensity; (c) distribution of O element in the transverse plane; (d) distribution of Ni element in the transverse plane; (e) distribution of Fe element in the transverse plane