Physikalisches Kolloquium: Prof. Dr. Gerd Schröder-Turk – Development of optical Gyroid nanostructures in green butterflies

Titel: Development of optical Gyroid nanostructures in green butterflies

Abstract:
Several green butterflies generate their green coloration as a photonic crystal effect using a 3D nanostructure known as the Gyroid. The structure of the mature butterfly nanostructures is easy to image by electron and X-ray microscopy and well characterised, and its photonic properties are well understood. However, the mechanisms by which the butterfly forms these nanostructures, and particularly how it stabilises a highly ordered geometry at the large length scale of 100s of nanometers, is not fully understood. In this talk, I will discuss our optical microscopy observations on living butterfly pupae that are suitably dissected to reveal the area of interest. Like any conventional microscopy, our optical data cannot resolve the nanostructure; it is below the diffraction limit. However, we can resolve the reflectances that the nanostructure causes. Together with electron microscopy analyses of tissue samples, these reflectances can be used to at least provide information of the timing of nanostructure development. When we carried out these analyses, we made the surprising finding that, at the early stages of development, the nanostructure is composed of fibrils woven together to form the 3D nanostructure; how it transitions to the smooth nanostructural form observed in mature butterflies is not currently known.

Sprecher / Speaker: Prof. Dr. Gerd Schröder-Turk
Kontakt / Contact: Prof. Dr. Ben Fabry