Tailored disorder

The transport of light in materials is determined by the dispersion relation. For natural materials, this is determined by material properties such as the refractive index and can only be influenced to a limited extent.

Three-dimensional microstructuring on the scale of the wavelength of light, on the other hand, allows the dispersion relation to be tailored. In periodic structures such as photonic crystals, the resulting band structure can be calculated using methods of solid state physics.

We investigate the question how the transport properties change when disorder is introduced into structures. Disorder can occur randomly due to variations in the manufacturing process. However, this proportion is very small on the scales considered. Much more exciting is tailor-made disorder, which is programmed directly into the structures by a random number generator. We compare this random disorder with deviations that are generated due to mathematical consequences that produce certain correlations. Such deterministically aperiodic structures allow us to vary the type and strength of the disorder and thus better understand the influence of disorder.

This is also interesting for an understanding of the diverse coloration in nature, since nature can produce a great coloration with very little material diversity just by structuring. Here, tailor-made disorder plays an essential role.