Coherent light scattering by blue feather barbs

Prum, Richard O.; Torres, Rodolfo H.; Williamson, Scott; Dyck, Jan

doi:10.1038/23838

Cited by 326 publications

(310 citation statements)

References 2 publications

Supporting

Mentioning

304

Contrasting

Unclassified

Order By: Relevance

“…Here, we further test the hypothesis that constructive interference of light scattered by three-dimensional quasi-ordered photonic nanostructures is responsible for the non-iridescent plumage structural colours found in diverse avian lineages [3,8,9]. We also quantitatively compare the SAXS data from hundreds of feather nanostructures with experimental scattering data from self-assembled, synthetic soft condensed matter systems.…”

Section: Self-assembly By Phase Separationmentioning

confidence: 99%

“…90 nm), low-resolution, two-dimensional slice of a three-dimensional nanostructure, such as aliasing, binning, etc. Nevertheless, most studies of avian structural colours have used twodimensional electron microscopy to characterize their underlying three-dimensional biophotonic nanostructures [3,[7][8][9]14,[17][18][19][21][22][23][24][25]. However, fundamental uncertainty remains about the exact organization of these three-dimensional amorphous feather barb nanostructures.…”

Section: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

“…Fourier analyses of TEM images were sufficiently accurate to falsify the century-old, single particle (Tyndall or Rayleigh, and Mie) scattering hypotheses, which assumed that the colour comes from wavelength-dependent light scattering properties of isolated, spatially uncorrelated scatterers [3,[7][8][9]16]. But two-dimensional Fourier power spectra of TEM images lack the resolution to account for the variation in reflectance features of these complex three-dimensional nanostructures [3,[7][8][9][17][18][19][20].…”

Section: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

“…Previous research using Fourier analysis of twodimensional transmission electron microscopy (TEM) images of amorphous barb nanostructures has documented their isotropic quasi-order from their ring-shaped twodimensional Fourier power spectra [3,[7][8][9]16]. Fourier analyses of TEM images were sufficiently accurate to falsify the century-old, single particle (Tyndall or Rayleigh, and Mie) scattering hypotheses, which assumed that the colour comes from wavelength-dependent light scattering properties of isolated, spatially uncorrelated scatterers [3,[7][8][9]16].…”

Section: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

“…28 species from 16 families [3]), but typically known to occur in one of two distinct morphologies. The channeltype nanostructures are characterized by a tortuous, interconnected bicontinuous network of air channels and b-keratin bars of similar widths and shapes (figure 2e) [3,[7][8][9]14]. The sphere-type nanostructures consist of a quasi-ordered close packing of spheroidal air cavities that are separated by b-keratin walls and frequently interconnected by tiny air passages (figure 2f ).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species

Saranathan

Forster

Noh

et al. 2012

J. R. Soc. Interface.

Self Cite

134

185

View full text Add to dashboard Cite

Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy b-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel-and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the singlescattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel-and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing b-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.

show abstract

Section: Self-assembly By Phase Separationmentioning

confidence: 99%