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In the fabrication processes of photonic crystals, structural disorder arises in the synthesised structures from the limitations in the resolution of the synthesis processes. Elucidating the structural-disorder influence helps reducing its optical effects and allows using it in technological applications. Natural photonic structures are interesting examples to investigate due to their resilience to structural defects. The benefit and cost of these defects are so far not understood. In this contribution, we investigated the structural disorder in one-dimensional photonic crystals occurring on the wings of beetles. We performed optical simulations allowing to assess the optical benefit and cost of such disorder.

The precise control of light–matter interactions is crucial for the majority of known biological organisms in their struggle to survive. Many species have evolved unique methods to manipulate light in their environment using a variety of physical effects including pigment-induced, spectrally selective absorption or light interference in photonic structures that consist of micro- and nano-periodic material morphologies. In their optical performance, many of the known biological photonic systems are subject to selection criteria not unlike the requirements faced in the development of novel optical technology. For this reason, biological light manipulation strategies provide inspiration for the creation of tunable, stimuli-responsive, adaptive material platforms that will contribute to the development of multifunctional surfaces and innovative optical technology. Biomimetic and bio-inspired approaches for the manufacture of photonic systems rely on self-assembly and bottom-up growth techniques often combined with conventional top-down manufacturing. In this regard, we can benefit in several ways from highly sophisticated material solutions that have convergently evolved in various organisms. We explore design concepts found in biological photonic architectures, seek to understand the mechanisms underlying morphogenesis of bio-optical systems, aim to devise viable manufacturing strategies that can benefit from insight in biological formation processes and the use of established synthetic routines alike, and ultimately strive to realize new photonic materials with tailor-made optical properties. This talk is focused on the identification of biological role model photonic architectures, a brief discussion of recently developed bio-inspired photonic structures, including mechano-sensitive color-tunable photonic fibers and reconfigurable fluid micro-lenses. Potentially, early-stage results in studying and harnessing the structure-forming capabilities of living cells that lie at the origin of many species’ ability to grow photonic materials will also be presented.

The spectral and angle-dependent optical properties of two scarab beetle species belonging to the genus Chrysina are presented. The species display broadband reflectivity and selectively reflect left-circularly polarized light. We use electron microscopy to detail the left-handed, twisted lamellar structure present in these biological systems and imaging scatterometry to characterize their bidirectional reflectance distribution function. We show that the broadband nature of the beetles’ reflectance originates due to the range of pitch dimensions found in the structure.

Surveys of the natural world reveal an extensive array of optical effects in a broad range of animal and insect species. While the aesthete may simply take delight in such phenomena, students of photonics have increasingly been prepared to look more closely; deriving understanding and inspiration from nature's optical ingenuity. By describing specific structural color examples in detail, within a general context of Lepidopteran microstructure classification, this review paper seeks to present an introduction to current work on butterfly photonics. Additionally, new but preliminary results and analysis are presented, that describe the structural color of a butterfly that exhibits a distinct 3D photonic crystal structure.