Structural coloration in caloenas nicobarica pigeons and refractive index modulated sensing

Ijaz Rashid, Muhammad Umair Hassan, Abbas Khandwalla, Rayan Mohammed Ameen, Ali Kemal Yetisen, Qing Dai, Haider Butt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
298 Downloads (Pure)


The Nicobar pigeon (Caloenas Nicobarica) belongs to the extinct dodo-bird family and has been declared as an endangered species. Here, microscopic and spectroscopic measurements are carried out on the bird's feathers to study the structural coloration originating from the barbule nanostructures. A range of color shades is recorded with changing viewing and illumination angles at different locations of the feathers. A spectacular variation in colors is generated by photonic structures; red, green, and blue and their blends are observed. Hydrophobicity of the optical material is also investigated. A contact angle of ≈156° is observed demonstrating it to be superhydrophobic. Experimental observations of the optical properties are analyzed on these feathers for sensing made possible due to the material and structural properties at the interface between barbule's surface and solution. An optical response is observed with a redshift in optical spectra with increasing refractive index of the solution, which is correlated with concentration values. The structural coloration in Nicobar pigeon can be adopted for many practical applications such as color selective filters, nonreflecting coatings, and refractive index-based sensing.

Original languageEnglish
JournalAdvanced Optical Materials
Early online date28 Feb 2018
Publication statusE-pub ahead of print - 28 Feb 2018


  • Coloration
  • Diffraction
  • Photonic structures
  • Refractive index
  • Scattering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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