Fig. 1. Images of micro/nano structures fabricated by the fs laser at the focal plane. The laser power and scanning speed were 20 W and 50 mm/s, respectively.

Fig. 2. Morphology of micro/nano structures induced by the fs laser at different defocusing distances: (a) 1.60 mm; (b) 1.62 mm; (c) 1.64 mm; (d) 1.66 mm; (e) 1.68 mm.

Fig. 3. Reflection spectra of the samples fabricated by the fs laser at different defocusing distances.

Fig. 4. SEM images of micro/nano hybrid structures fabricated by the fs laser at different scanning intervals: (a) 50 µm; (b) 40 µm; (c) 30 µm; (d) 20 µm.

Fig. 5. Three-dimensional morphology of hybrid micro/nano structures with different scanning intervals: (a) 50 µm; (b) 40 µm; (c) 30 µm; (d) 20 µm.

Fig. 6. Reflection spectra of the samples fabricated by the fs laser at different scanning intervals.

Fig. 7. Blackened sample fabricated by the circularly polarized laser and its morphology.

Fig. 8. Reflection spectra of the samples fabricated by linearly and circularly polarized fs lasers, respectively.

Fig. 9. Mechanism of optical absorption of micro/nano hybrid structures processed by the circularly polarized laser.