Development of new transmissive light materials by "control of randomness"

Biometrics combines principles from engineering, physics, chemistry, biology and informatics and applies them to create materials, systems and machines that mimic biological processes. The idea is to mimic things that exist naturally in order to develop artificial things with novel properties. Dr Akira Saito, Department of Precision Engineering, Osaka University, Japan, is working to develop new transmissive light materials inspired by butterflies. The blue Morpho butterfly has brilliant blue wings and scientists have discovered that the colour is attributed to a specific nanostructure that has both order and disorder. Saito and the team have been working to artificially reproduce this coloration and have proven the optical principles of the Morpho butterfly's reflection, progressed various application technologies and, more recently, found a new direction - the transfer from reflection to transmission which has applications in window technologies. The researchers have developed a daylight window that satisfies at once all conditions of high transmittance, wide angular spread, low colour dispersion, and spread-shape controllability and have also realised the diffuser that will enable the light source to 'see the object correctly' in terms of the colour rendering. This has potential to be used in fields that rely on different forms of lighting, including fine arts, surgery and various types of photography. The important methods that Saito and the team have used in their research are nanofabrication (including lithography, etching and nanoimprinting), structural and optical evaluation (SEM and AFM, measurement of reflectivity and transmittance versus angle with spectroscopy), and numerical simulation.