Graded pitch profile for the helicoidal broadband reflector and left-handed circularly polarizing cuticle of the scarab beetle Chrysina chrysargyrea

Mendoza-Galván, A.; Río, Lía Fernández del; Järrendahl, Kenneth; Arwin, Hans

doi:10.1038/s41598-018-24761-w

Cited by 20 publications

(25 citation statements)

References 37 publications

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“…Equation (3) is the extended version of those equations valid for a single pitch structure ( λ o = n av P o and Δ λ = Δ nP o , respectively), when considering chiral chirped arrangements. It is conceptually erroneous to apply the equations λ o = n av P o and Δ λ = Δ nP o when considering helical structures with graded pitches, as reported in [58], where λ o was estimated from n av P o to show that the depth-dependent pitch values obtained for the cuticle of silver-like C. chrysargyrea scarabs, based on the analysis of SEM images, are too small to justify the presence of a reflection band extending towards the NIR [35,58]. In these cases, the correct way to explain the effective width of the reflection band is by application of Equations (4)–(6) to obtain the minimum value of λ − and the maximum value of λ + for a specific depth dependence of the pitch.…”

Section: Resultsmentioning

confidence: 99%

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles

et al. 2018

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A unified description involving structural morphology and composition, dispersion of optical constants, modeled and measured reflection spectra and photonic crystal characterization is devised. Light reflection spectra by the cuticles of scarab beetles (Chrysina chrysargyrea and Chrysina optima), measured in the wavelength range 300–1000 nm, show spectrally structured broad bands. Scanning electron microscopy analysis shows that the pitches of the twisted structures responsible for the left-handed circularly polarized reflected light change monotonically with depth through the cuticles, making it possible to obtain the explicit depth-dependence for each cuticle arrangement considered. This variation is a key aspect, and it will be introduced in the context of Berreman’s formalism, which allows us to evaluate reflection spectra whose main features coincide in those displayed in measurements. Through the dispersion relation obtained from the Helmholtz’s equation satisfied by the circular components of the propagating fields, the presence of a photonic band gap is established for each case considered. These band gaps depend on depth through the cuticle, and their spectral positions change with depth. This explains the presence of broad bands in the reflection spectra, and their spectral features correlate with details in the variation of the pitch with depth. The twisted structures consist of chitin nanofibrils whose optical anisotropy is not large enough so as to be approached from modeling the measured reflection spectra. The presence of a high birefringence substance embedded in the chitin matrix is required. In this sense, the presence of uric acid crystallites through the cuticle is strongly suggested by frustrated attenuated total reflection and Raman spectroscopy analysis. The complete optical modeling is performed incorporating the wavelength-dependent optical constants of chitin and uric acid.

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Section: Resultsmentioning

confidence: 99%

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles

et al. 2018

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“…A review with a focus on biomimetics is given by Lenau and Barfoed [21]. During the last decade, Mueller-matrix studies on beetle cuticles have been introduced by Goldstein [22], Hodgkinson [23] and our group [7,9,[24][25][26][27][28].…”

Section: Structural Optical Activity In Cuticle From Cetonia Auratamentioning

confidence: 99%

Optical Chirality Determined from Mueller Matrices

et al. 2021

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Optical chirality, in terms of circular birefringence and circular dichroism, is described by its electromagnetic and magnetoelectric material tensors, and the corresponding optical activity contributes to the Mueller matrix. Here, spectroscopic ellipsometry in the spectral range 210–1690 nm is used to address chiral phenomena by measuring Mueller matrices in transmission. Three approaches to determine chirality parameters are discussed. In the first approach, applicable in the absence of linear polarization effects, circular birefringence and circular dichroism are evaluated directly from elements of a Mueller matrix. In the second method, differential decomposition is employed, which allows for the unique separation of chirality parameters from linear anisotropic parameters as well as from depolarization provided that the sample is homogeneous along the optical path. Finally, electromagnetic modeling using the Tellegen constitutive relations is presented. The last method also allows structural effects to be included. The three methods to quantify optical chirality are demonstrated for selected materials, including sugar solutions, α-quartz, liquid crystals, beetle cuticle, and films of cellulose nanocrystals.

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“…2B). First, the structure called rotation is the Bouligand structure observed in biological composites [9,[37][38][39] and extensively reproduced in fibrous composites, and adapted to platelet inclusions. This structure has been hypothesized to filter shear waves [9].…”

Section: Modeling Approachmentioning

confidence: 99%

Modeling the effect of microstructure on elastic wave propagation in platelet-reinforced composites and ceramics

Ferrand

2019

Composite Structures

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Dense ceramics are irreplaceable in applications requiring high mechanical stiffness, chemical and temperature resistance and low weight. To improve their toughness, ceramics can be reinforced with elongated inclusions. Recent manufacturing strategies have been developed to control the orientations of disc-like microparticles in polymeric and ceramic matrices and to build periodic microstructures. Given the infinite number of possible microstructures available, modeling tools are required to select the potentially best design. Periodic microstructures can be involved in elastic wave scattering to dissipate mechanical energy from vibrations. In this paper, a model is proposed to determine the frequency bandgaps associated to periodic architectures in composites and ceramics and the influence of microstructural parameters are investigated. The results are used to define guidelines for the future fabrication of hard bulk ceramic materials that combine traditional ceramic's properties with high vibration resistance. Ceramics are advantageous in many high technological applications such as turbine blades, pipelines or tiles of spacecrafts thanks to their chemical inertness, stability until high temperature and high strength and hardness. However, non-piezoelectric ceramic do not present the damping capacity that is required to dissipate the energy from high mechanical impacts and vibrations. Instead, microcracking will occur [1]. To prevent failure of structural parts submitted to vibrations and impacts, reinforced composite laminates are replacing fragile ceramics. However, polymer-based composites cannot sustain the temperatures and harsh environments experienced by turbine blades or space shuttles. Ceramic matrix composites (CMC) are ceramics reinforced with inclusions to increase their toughness and strength [2]. However, their vibration resistance should be further improved for long timer performance under high mechanical dynamic solicitations.

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Graded pitch profile for the helicoidal broadband reflector and left-handed circularly polarizing cuticle of the scarab beetle Chrysina chrysargyrea

Cited by 20 publications

References 37 publications

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles

Optical Chirality Determined from Mueller Matrices

Modeling the effect of microstructure on elastic wave propagation in platelet-reinforced composites and ceramics

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