Fig. 1. Schematic diagram of solution
Fig. 2. Scheme of surface pattern preparation using laserinduced periodic surface nanostructures
Fig. 3. Optical photographs of periodic nanostructures induced by nanosecond lasers at different fluences and scanning rates on mirror polished 304 stainless steel surfaces
Fig. 4. Effects of scanning rate and fluence on periodic pattern formation
Fig. 5. Effects of ripple sharpness and regularity on coloration. (a)--(c) Coloring renderings of three experimental conditions marked in figure 4 by circle, square, and triangle, respectively; (d)--(f) SEM images corresponding to Fig. 5(a)--(c); (g) frequency spectrum of Fourier transform of SEM images at ky=0 μm-1
Fig. 6. Fourier transform spectra of SEM image. (a)--(c) Two-dimensional Fourier transforms corresponding to Figs. 5 (e), (f), and (d), respectively
Fig. 7. Direction control of ripples by polarization rotator. (a) Optical images of periodic ripples with different orientation angle (φ); (b) periodic ripple direction angle (φ) dependence on rotation angle (α) of polarizer
Fig. 8. Effect of polarization direction on coloring
Fig. 9. Evolution of each component of RGB color space
Fig. 10. Flower patterns on surface of mirror polished 304 stainless steel based on periodic nanostructures. (a) Main body of flower appears orange-red when viewing angle is large; (b) flower body turns blue when viewing angle is reduced; (c) main body of flower shows green when viewing angle is further reduced
Fig. 11. Optical photographs of school logo on mirror polished stainless-steel surface
Fig. 12. Color effect of complex shapes on free-form surfaces