title: Controlled fluorescence in a beetle's photonic structure and its sensitivity to environmentally induced changes.
abstract: The scales covering the elytra of the male Hoplia coerulea beetle contain fluorophores embedded within a porous photonic structure. The photonic structure controls both insect colour (reflected light) and fluorescence emission. Herein, the effects of water-induced changes on the fluorescence emission from the beetle were investigated. The fluorescence emission peak wavelength was observed to blue-shift on water immersion of the elytra whereas its reflectance peak wavelength was observed to red-shift. Time-resolved fluorescence measurements, together with optical simulations, confirmed that the radiative emission is controlled by a naturally engineered photonic bandgap while the elytra are in the dry state, whereas non-radiative relaxation pathways dominate the emission response of wet elytra.
authors.affiliation: Department of Physics, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium s.mouchet@exeter.ac.uk.|School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.
authors.forename: Sébastien R
authors.identifier: 0000-0001-6611-3794
authors.initials: SR
authors.lastname: Mouchet
authors.affiliation: Department of Physics, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: Michaël
authors.identifier: 0000-0002-4571-0212
authors.initials: M
authors.lastname: Lobet
authors.affiliation: Department of Physics, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: Branko
authors.identifier: 0000-0003-0203-7897
authors.initials: B
authors.lastname: Kolaric
authors.affiliation: L-Luminescent Lanthanide Lab, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Kaczmarek
authors.affiliation: L-Luminescent Lanthanide Lab, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent, Belgium.
authors.forename: Rik
authors.identifier: 0000-0001-7091-6864
authors.initials: R
authors.lastname: Van Deun
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Vukusic
authors.affiliation: Department of Physics, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Deparis
authors.affiliation: Department of Physics, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: Eloise
authors.initials: E
authors.lastname: Van Hooijdonk
mesh_terms: D060105:Animal Shells / Q000502:physiology*; D000818:Animals; D001517:Coleoptera / Q000502:physiology*; D003116:Color; D004777:Environment; D005453:Fluorescence; D008297:Male; D017785:Photons; D014867:Water
chemical_list: D014867:Water
keywords: beetle scale; fluorescence; natural photonic crystal; photonic bandgap materials; structural colour