Fig. 1. Origin of extrinsic chiral characteristic and structure characterization of the hierarchical chiral plasmonic patterns.

a, b Schematic images of the a chiral plasmonic structures under light illumination. b Enlarged image showing the incident oblique angles (θ, ϕ) for the irradiated light. c, d Schematic images of hierarchical c LH- and d RH-chiral plasmonic patterns with corresponding OM images (scale bar of OM images: 50 μm). e Enlarged OM image of the LH-chiral plasmonic patterns, showing the central (cobalt), lower left (olive), and upper right (orange) parts of the protruding area of the micropattern (scale bar: 20 μm). f SEM images of the central part (cobalt area in Fig. 1e) of the protruding area of the micropattern and an enlarged image (scale bar: 10 μm and 1 μm, respectively) g, h SEM images of the g lower left (green area in Fig. 1e), and the h upper right (amber colored area in Fig. 1e) parts of the protruding area of the micropattern (scale bar: 2 μm). i Schematic images and j enlarged images of original (blue), vertical (red), and diagonal (green) grating patterns for LH patterns. k Schematic images of original grating patterns (left), additionally formed vertical nanopatterns (middle), and diagonal nanopatterns (right) for LH-chiral plasmonic patterns with θ and ϕ for the incident light (pink arrow: incident direction of light).