Dual gratings interspersed on a single butterfly scale |
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Authors: | Abigail L Ingram Virginie Lousse Andrew R Parker Jean Pol Vigneron |
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Affiliation: | 1.Natural History Museum, Cromwell Road, London SW7 5BD, UK;2.Département de Physique, Facultés Universitaires Notre-Dame de la Paix, 61 Rue de Bruxelles, 5000 Namur, Belgium;3.Ginzton Laboratory, Stanford University, Stanford, CA 94305, USA;4.School of Biological Sciences, University of Sydney, NSW 2006, Australia |
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Abstract: | Iridescent butterfly wing colours result from the interaction of light with sub-micrometre structures in the scales. Typically, one scale contains one such photonic structure that produces a single iridescent signal. Here, however, we show how the dorsal wings of male Lamprolenis nitida emit two independent signals from two separate photonic structures in the same scale. Multiple independent signals from separate photonic structures within the same sub-micrometre device are currently unknown in animals. However, they would serve to increase the complexity and specificity of the optical signature, enhancing the information conveyed. This could be important during intrasexual encounters, in which iridescent male wing colours are employed as threat displays. Blazed diffraction gratings, like those found in L. nitida, are asymmetric photonic structures and drive most of the incident light into one diffraction order. Similar gratings are used in spectrometers, limiting the spectral range over which the spectrometer functions. By incorporating two interchangeable gratings onto a single structure, as they are in L. nitida, the functional range of spectrometers could be extended. |
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Keywords: | butterfly wing colour iridescent signal photonic structure blazed diffraction grating spectrometer |
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