Fig. 5

Broadband mirror with a silver color and good flexibility (a). Photograph illustrating the mirror-like reflection of the F3 sample (b). Cross-sectional SEM images of the fractured F3 sample showing the periodically stacked helical arrays with well-controlled helical pitches (c). Schematic illustration of the helical pitch distribution of the multilayer stacked nanostructure of F3 (d)