Double scattering of light from biophotonic nanostructures with short-range order

TL;DR

This paper explores how double scattering in short-range ordered biophotonic nanostructures produces distinct secondary color peaks, revealing a unique mechanism behind non-iridescent structural coloration in nature.

Contribution

It uncovers the role of double scattering in color production in short-range ordered nanostructures, a phenomenon not present in periodic or random structures.

Findings

Secondary peaks arise from double scattering in short-range ordered structures.

Double scattering explains unique non-iridescent coloration in bird feathers.

Experimental and numerical results confirm the mechanism.

Abstract

We investigate the physical mechanism for color production by isotropic nanostructures with short-range order in bird feather barbs. While the primary peak in optical scattering spectra results from constructive interference of singly-scattered light, many species exhibit secondary peaks with distinct characteristic. Our experimental and numerical studies show that these secondary peaks result from double scattering of light by the correlated structures. Without an analog in periodic or random structures, such a phenomenon is unique for short-range ordered structures, and has been widely used by nature for non-iridescent structural coloration.