Members of the order Coleoptera are sometimes referred to as 'living jewels', in allusion to the strikingly diverse array of iridescence mechanisms and optical effects that have arisen in beetles. A number of novel and sophisticated reflectance mechanisms have been discovered in recent years, including three-dimensional photonic crystals and quasi-ordered coherent scattering arrays. However, the literature on beetle structural coloration is often redundant and lacks synthesis, with little interchange between the entomological and optical research communities. Here, an overview is provided for all iridescence mechanisms observed in Coleoptera. Types of iridescence are illustrated and classified into three mechanistic groups: multilayer reflectors, three-dimensional photonic crystals and diffraction gratings. Taxonomic and phylogenetic distributions are provided, along with discussion of the putative functions and evolutionary pathways by which iridescence has repeatedly arisen in beetles.

Recents works deal with the optical transmission on arrays of subwavelength holes in a metallic layer deposited on a dielectric substrate. Making the system as realistic as possible, we perform simulations to enlighten the experimental data. This paper proposes an investigation of the optical properties related to the transmission of such devices. Numerical simulations give theoretical results in good agreement with experiment and we observe that the transmission and reflection behaviour correspond to Fano's profile correlated with resonant response of the eigen modes coupled with nonhomogeneous diffraction orders. We thus conclude that the transmission properties observed could conceivably be explained as resulting from resonant Wood's anomalies.

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Nature began developing photonic nanoarchitectures millions of years before humankind. Often, in the living world, color is a communication channel that may influence the chance of the individual surviving as well as the chance to reproduce. Therefore, natural color-generating structures are highly optimized by many millennia of evolution. In this review, a survey is presented of the development of natural photonic crystal-type nanoarchitectures occurring in butterflies and beetles from the standpoint of physics and materials science, covering the past ten years. One-, two-, and three-dimensional structures are reviewed, emphasizing the role that disorder, or irregularity, may play in natural nanoarchitectures to achieve certain visual effects. The characterization, modeling methods, and rapidly growing number of bioinspired or biomimetic applications are discussed.

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We report on the first measurements by high-resolution electron-energy-loss spectroscopy of the elementary excitations of C60 thin films deposited on Si(100). By varying the primary electron energy, the spectrum extending from the far ir to the far vuv has been investigated. Many spectral features are comparable to earlier observations by photon, photoelectron, and neutron spectroscopies. New molecular excitations are revealed including the lowest electronic excitation at 1.5 eV and collective excitations at 6.3 and 28 eV.

The band structure of graphite with the hypothetical simple hexagonal structure has been investigated near the Fermi energy, using a tight-binding approximation. Some general features of the structure of the~bands in the neighborhood of the zone edge are obtained and are expressed in terms of appropriate parameters. The Fermi surface is analyzed. The density of states and the resulting behavior near the Fermi level are compared to the results obtained for the Bernal structure (Slonczewski-Weiss-McClure model) and for the rhombohedral structure (Haering-McClure model). Possible application to disordered graphite (turbostratic) is also discussed.

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