Photonic Crystals in Biology: Study and Mimicry of Butterfly Wings
INTELLECTUAL MERIT: The brilliant colors found on the bodies of butterflies and beetles have attracted enormous attention from biologists, physicists, chemists and more recently from materials scientists. It is now well recognized that many of these colors are due to the nano-structures or sub-wavelength structures on the surface of the wing scales, thus becoming natural analogues of a class of optical materials known as photonic crystals. While it is recognized that structural colors are not the only butterfly color production mechanism, this proposal is limited to instances where structural color production is the primary source of color on the butterfly wings. The focus here is on a variety of butterflies that produce color by structural means. Specifically, the PI intends to characterize the optics of individual wing scales using the methods developed in his laboratory, model the optical properties of the wing scales both from the point of view of color science as well as from an optics perspective, and mimic/replicate the structure of wing scales that produce the color. It is also proposed to mimic the optical character of the butterfly Papilio palinurus, which produces its green coloration by what is termed color stimulus synthesis (CSS) by using bottom-up self-assembly process. The scientific merit of the proposal lies in the fact that it will attempt to characterize a variety of (individual) wing scales of butterflies that possess structural colors, and model their optical properties using the language of color science as well as the language of photonic crystals.
BROADER IMPACTS: The broader impacts of the proposed activities take at-least three forms: (i) student education in a very cross-disciplinary fashion; (ii) outreach activities to high school students and high school science teachers and more recently (iii) interacting with the San Francisco Exploratorium and participating in informal science education. The students working on this project will be trained in a very interdisciplinary fashion where they will have to understand the biology to some extent while being well versed in optical physics ? and in order to replicate these structures they will also have to be quite comfortable with chemistry. The fact that butterflies are colored due to physical structures lends itself beautifully to teach optics to high school children. Hence, the PI goes to local high schools and also runs workshops on optics for high school science teachers at least once a year. More recently he has been working with the San Francisco Exploratorium to disseminate his results to the general public as a means of informal science education, and he will continue to collaborate with the Exploratorium, as it is quite rewarding to disseminate his work to the general public in this forum.
