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Title: Photonic structures inspired by nature
Author: Kolle, Mathias
ISNI:       0000 0003 5580 3065
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2014
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The vivid colours found in nature mesmerise optics experts and laymen alike. Despite the detailed scientific understanding of optics, the astonishingly varied colour palette found in nature often surpasses the optical effects that can be generated by technological means. The common characteristic feature of these so-called structural colours are intricate patterns on the 1nm to 1 μm length scale. The increasing understanding of natural photonic structures begets the question, how these can be mimicked by technological processes. The scientific motivation for the replication of natural materials concerns the study of the natural systems themselves. Since the study of the natural photonic materials is often complicated by their disorder and intrinsic complexity, it is often beneficial to construct an idealised replica. Secondly, since natural structures are all unique, the variation of structural parameters afforded by structural replication facilitates the systematic study of the natural originals. There is also an increasing technological interest in complex optical materials, in particular in the field of security labelling. Mathias Kolle's doctoral thesis describes four different aspects of natural or natureinspired optics. The principle of using replicas (rather than the natural structure itself) is demonstrated, for example, in the study of the colour response of plant petals and their role for pollinator recognition. Replica of the plant petal surfaces provided more robust samples for optical studies than the delicate petals themselves and artificially made "plant petals" were used in bee studies to explore the role of structural colour for bee recognition. This study of a natural system is supplemented by several nature-inspired artificially made optical structures. Particularly interesting is the mimetic manufacture of the colourful wing-scales of the Papilio blumei butterfly. The important aspect here is the combination of a self-assembly process with an Ångström-precision layer-deposition technique, which allows the facile manufacture of large-area structured materials with the required optical quality. This experiment also illustrates the role of fortuitous experimental design. One of the key results of this doctoral thesis, giving rise to the striking optical effect on the thesis cover, was not achieved by careful planning but by the accidental omission of one step during sample preparation. This does however, by no means lessen the scientific achievement, which in this case lies in the detailed understanding of the accidentally produced optical structure.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral