Widely Applied Mathematics Seminars

Structural Color: From Birds to Materials

Vinothan Manoharan, Wagner Family Professor of Chemical Engineering and Professor of Physics, Harvard University

Thursday, Oct 12, 2023

Most colored materials owe their color to the absorption of light:  certain wavelengths are absorbed and others transmitted. The color arises from the remaining wavelengths that are reflected or scattered back to the observer. In nature we often see a different type of coloration, known as structural color, which comes from interference or diffraction of light and not absorption: certain wavelengths are transmitted, while others constructively interfere and are reflected.  Structural colors are common in birds and particularly in blue feathers, which consist of disordered arrays of pores that scatter light.  I will discuss our work on making synthetic systems that mimic the bird feathers. We make these materials by packing spheres into a disordered arrangement. I will present results based on experiments, scattering theory, and geometry that shed light on the physics of structural colors -- and why blue structural color is so much more common than red.

Speaker Bio

Vinothan N. Manoharan is the Wagner Family Professor of Chemical Engineering and Professor of Physics at Harvard University.  His research focuses on understanding how systems containing many particles suspended in a liquid — such as nanoparticles, proteins, or cells — organize themselves into ordered structures like crystals, viruses, and even living tissues.  The goal is to discover new, general physical principles that underlie complex systems and to apply these principles to practical problems in materials science, nanotechnology, and medicine. Manoharan received his PhD from the University of California, Santa Barbara in 2004 and worked as a postdoctoral researcher at the University of Pennsylvania before arriving at Harvard in 2005. He has served as Director of Graduate Studies in the Physics Department and as a member of Harvard’s Task Force on Inclusion and Belonging.


David Nelson


Jessica Brenn