Composite organic-inorganic butterfly scales: Production of photonic structures with atomic layer deposition

Abstract

Recent advances in the photonics and optics industries have produced great demand for ever more sophisticated optical devices, such as photonic crystals. However, photonic crystals are notoriously difficult to manufacture. Increasingly, therefore, researchers have turned towards naturally occurring photonic structures for inspiration and a wide variety of elaborate techniques have been attempted to copy and harness biological processes to manufacture artificial photonic structures. Here, we describe a simple, direct process for producing an artificial photonic device by using a naturally occurring structure from the wings of the butterfly Papilio blumei as a template and low-temperature atomic layer deposition of TiO2 to create a faithful cast of the structure. The optical properties of the organic-inorganic diffraction structures produced are assessed by normal-incidence specular reflectance and found to be well described by multilayer computation method using a two-dimensional photonic crystal model. Depending on the structural integrity of the initially sealed scale, it was found possible not only to replicate the outer but also the inner and more complex surfaces of the structure, each resulting in distinct multicolor optical behavior as revealed by experimental and theoretical data. In this paper, we also explore tailoring the process to design composite skeleton architectures with desired optical properties and integrated multifunctional (mechanical, thermal, optical, fluidic) properties.

Mimicking the colourful wing scale structure of the Papilio blumei butterfly

“…1). Although the P. blumei wing scales have previously been used as a template for atomic layer deposition (ALD) 9 , such an approach is not suitable for accurate replication of the internal multilayer structure on large surface areas.The bright green coloured areas on P. blumei and P. palinurus wings result from a juxtaposition of blue and yellow-green light reflected from different microscopic regions on the wing scales. Light microscopy reveals that these regions are the centres (yellow) and edges (blue) of concavities that are 5-10 mm wide, clad with a perforated cuticle multilayer 7 (Fig.…”

“…1). Although the P. blumei wing scales have previously been used as a template for atomic layer deposition (ALD) 9 , such an approach is not suitable for accurate replication of the internal multilayer structure on large surface areas.…”

Artificial selection for structural color on butterfly wings and comparison with natural evolution

“…By examining how these species/populations evolve different colors, it is possible to identify the minimal amount of morphological change that results in significant color variation. Furthermore, this research may serve as an inspiration for future application of similar evolutionary principles to the design of photonic devices for color tuning, light trapping, or beam steering (2,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). From an evolutionary biology point of view, we are curious to examine how structural colors respond to selection pressure and whether there is sufficient standing genetic variation in natural populations to allow the rapid evolution of novel colors.…”

The abstraction transition taxonomy

“…Pair programming has been effectively used in the classroom [15] and is an effective way to encourage students to engage in confident practice while learning and consequently doing better in their programming. [16] Coding Dojos [17] harken back to something like the masterapprentice model to support acculturation. Seemingly not formally studied, Coding Dojos are places where programmers can go and watch others program or be watched programming.…”