Zs. Bálint

Photonic nanoarchitectures occurring in butterfly scales as selective gas/vapor sensors

Photonic band gap material type nanoarchitectures occurring in the wing scales of butterflies possessing structural color were investigated as selective gas/vapor sensors. From 20 examined butterfly species all showed selective sensing when various volatile organic compounds were introduced as additives in ambient air. Four butterflies species: Chrysiridia ripheus (Geometridae), Pseudolycena marsyas, Cyanophrys remus (both Lycaenidae) and Morpho aega (Nymphalidae) were selected to demonstrate the possibilities of selective sensing offered by these natural nanoarchitectures. Each butterfly species gives characteristic response both for species, i.e., for its typical nanoarchitecture, and for the seven test vapors used. Fast response time, reproducible and concentration dependent signals are demonstrated.

Wing scale microstructures and nanostructures in butterflies − natural photonic crystals

The aim of our study was to investigate the correlation between structural colour and scale morphology in butterflies. Detailed correlations between blue colour and structure were investigated in three lycaenid subfamilies, which represent a monophylum in the butterfly family Lycaenidae (Lepidoptera): the Coppers (Lycaeninae), the Hairstreaks (Theclinae) and the Blues (Polyommatinae). Complex investigations such as spectral measurements and characterization by means of light microscopy, scanning electron microscopy and transmission electron microscopy enabled us to demonstrate that: (i) a wide array of nanostructures generate blue colours; (ii) monophyletic groups use qualitatively similar structures; and (iii) the hue of the blue colour is characteristic for the microstructure and nanostructure of the body of the scales.

Bioinspired artificial photonic nanoarchitecture using the elytron of the beetle Trigonophorus rothschildi varians as a 'blueprint'.

An unusual, intercalated photonic nanoarchitecture was discovered in the elytra of Taiwanese Trigonophorus rothschildi varians beetles. It consists of a multilayer structure intercalated with a random distribution of cylindrical holes normal to the plane of the multilayer. The nanoarchitectures were characterized structurally by scanning electron microscopy and optically by normal incidence, integrated and goniometric reflectance measurements. They exhibit an unsaturated specular and saturated non-specular component of the reflected light. Bioinspired, artificial nanoarchitectures of similar structure and with similar properties were realized by drilling holes of submicron size in a multilayer structure, showing that such photonic nanoarchitectures of biological origin may constitute valuable blueprints for artificial photonic materials.

Temperature and saturation dependence in the vapor sensing of butterfly wing scales

The sensing of gasses/vapors in the ambient air is the focus of attention due to the need to monitor our everyday environment. Photonic crystals are sensing materials of the future because of their strong light-manipulating properties. Natural photonic structures are well-suited materials for testing detection principles because they are significantly cheaper than artificial photonic structures and are available in larger sizes. Additionally, natural photonic structures may provide new ideas for developing novel artificial photonic nanoarchitectures with improved properties. In the present paper, we discuss the effects arising from the sensor temperature and the vapor concentration in air during measurements with a photonic crystal-type optical gas sensor. Our results shed light on the sources of discrepancy between simulated and experimental sensing behaviors of photonic crystal-type structures. Through capillary condensation, the vapors will condensate to a liquid state inside the nanocavities. Due to the temperature and radius of curvature dependence of capillary condensation, the measured signals are affected by the sensor temperature as well as by the presence of a nanocavity size distribution. The sensing materials used are natural photonic nanoarchitectures present in the wing scales of blue butterflies.

Quasiordered photonic band gap materials of biologic origin: butterfly scales

Individual, unsupported scales of two male butterflies with dorsal blue and ventral green color were compared by microscpectrometric measurements, optical and electronic microscopy. All the scales are colored by photonic band gap type materials built of chitin (n = 1.58) and air. The different scales are characterized by different degrees of order from fully ordered single crystalline blue scales of the Cyanophrys remus butterfly through polycrystalline green scales on the ventral side of the same butterfly, to the most disordered dorsal blue scales of the Albulina metallica, where only the distance of the first neighbors is constant. The different scale nanoarchitectures and their properties are compared.

Photonic crystal type nanoarchitectures in butterfly wing scales

Photonic crystals also called Photonic Band Gap (PBG) materials — are periodic dielectric composite structures, which affect the propagation of the light. These materials are intensively studied since two decades [1, 2], because of perspectives of their applications in optical devices, textiles and colorants. The diversity of photonic crystal type nanoarchitectures found in Nature is also in the focus of researchers’ attention. Living organisms, during millennia of evolution, achieved very complex and highly optimized micro- and nanostructures not only for interaction with visible light but also for other specified functions as for example UV protection, thermal regulation or adhesion. A very remarkable attribute is that these nanostructures are produced by a limited range of materials, which offers only a moderate refractive index contrast (1/1.6). The investigation of natural nanostructures leads to the knowledge that can be applied in the design of artificial biomimetic materials with photonic properties and can reduce the engineering effort in designing these materials and costs of their fabrication.

Frederick W. Goodson and his contribution to the taxonomy of neotropical hairstreak butterflies (Lepidoptera: Lycaenidae: Eumaeini)

Abstract F. W. Goodsons work has often been confused with that of A. L. Goodson and work by the former sometimes attributed to the latter. Two manuscripts of F. W. Goodson found in the General Library of The Natural History Museum in London, eight hand‐written notes, and four wing preparations for butterfly wing venation studies left in the Lycaenidae General Collection are described and catalogued. Nineteen species‐group names of neotropical eumaeine lycaenids either described or revised by F. W. Goodson are reviewed. Twenty‐four primary (holo‐, lecto‐ or syntypes) and 12 secondary (paralectotype) specimens representing nominal taxa described by F. W. Goodson have been studied and databased. Two new synonyms and five new combinations are established, and six lectotypes designated unintentionally are recognized. One subsequent lectotype designation is invalidated. Three neotypes and one lectotype are designated.