Morpho

Abstract: Tropical Morpho butterflies are famous for their brilliant iridescent colours, which arise from ordered arrays of scales on their wings. Here we show that the iridescent scales of the Morpho sulkowskyi butterfly give a different optical response to different individual vapours, and that this optical response dramatically outperforms that of existing nano-engineered photonic sensors. The reflectance spectra of the scales provide information about the nature and concentration of the vapours, allowing us to identify a range of closely related vapours–water, methanol, ethanol and isomers of dichloroethylene when they are analysed individually. By comparing the reflectance as a function of time for different vapours, we deduce that wing regions with scale structures of differing spatial periodicity give contributions to the overall spectral response at different wavelengths. Our optical model explains the effect of different components of the wing scales on the vapour response, and could steer the design of new man-made optical gas sensors.

Abstract: Structural colour in the Morpho butterfly originates from submicron structure within a scale and, for over a century, its colour and reflectivity have been explained as interference of light due to the multilayer of cuticle and air. However, this model fails to explain the extraordinarily uniform colour of the wing with respect to the observation direction. We have performed microscopic, optical and theoretical investigations, and have found that the separate lamellar structure with irregular heights is extremely important. Using a simple model, we have shown that the combined action of interference and diffraction is essential for the structural colour of the Morpho butterfly.

Abstract: Thin-film color reflectors inspired by Morpho butterflies are fabricated. Using a combination of directional deposition, silica microspheres with a wide size distribution, and a PDMS (polydimethylsiloxane) encasing, a large, flexible reflector is created that actually provides better angle-independent color characteristics than Morpho butterflies and which can even be bent and folded freely without losing its Morpho-mimetic photonic properties.

Abstract: Three-dimensional (3D) analysis is an essential tool to obtain quantitative results from 3D datasets. Considerable progress has been made in 3D imaging techniques, resulting in a growing need for more flexible, complete analysis packages containing advanced algorithms. At the Centre for X-ray Tomography of the Ghent University (UGCT), research is being done on the improvement of both hardware and software for high-resolution X-ray computed tomography (CT). UGCT collaborates with research groups from different disciplines, each having specific needs. To meet these requirements the analysis software package, Morpho+, was developed in-house. Morpho+ contains an extensive set of high-performance 3D operations to obtain object segmentation, separation, and parameterization (orientation, maximum opening, equivalent diameter, sphericity, connectivity, etc.), or to extract a 3D geometrical representation (surface mesh or skeleton) for further modeling. These algorithms have a relatively short processing time when analyzing large datasets. Additionally, Morpho+ is equipped with an interactive and intuitive user interface in which the results are visualized. The package allows scientists from various fields to obtain the necessary quantitative results when applying high-resolution X-ray CT as a research tool to the nondestructive investigation of the microstructure of materials.