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Fossilized Biophotonic Nanostructures Reveal the Original Colors of 47-Million-Year-Old Moths

Figure 3

2-D Fourier analysis and reflectance microspectrophotometry of structurally colored scales from the basal part of the dorsal forewing.

(A, C) Transmission electron micrographs of longitudinal (A) and transverse (C) sections. (B, D) 2-D Fourier power spectra of nanostructures in (A) and (C), respectively. Color scale (blue to red) indicates the relative magnitude of the squared Fourier components, which are dimensionless quantities. Direction from the origin indicates the direction of the 2-D component waves in the image, and the distance from the origin indicates the spatial frequency (cycles/nm) of each Fourier component. (E) Radial average of power spectrum in (B). Shaded area indicates the range of spatial frequencies that produces coherent scattering of visible wavelengths. (F) Measured and Fourier predicted reflectance spectra for nanostructure in (A). Scale bars: (A, C), 500 nm.

Figure 3