scholarly journals The wing scales of the Mother-of-pearl butterfly, Protogoniomorpha parhassus, are thin film reflectors causing strong iridescence and polarization

2021 ◽  
Author(s):  
Doekele G. Stavenga
Keyword(s):  
Thin Film ◽  
Communication System ◽  
Effective Communication ◽  
Spectral Shape ◽  
Degree Of Polarization ◽  
Structural Color ◽  
Light Interference ◽  
Reflected Light ◽  
Intraspecific Communication ◽  
Wing Scales

The dorsal wings of the Mother-of-pearl butterfly, Protogoniomorpha parhassus, display an angle-dependent pink, structural color. This effect is created by light interference in the lower lamina of the wing scales, which acts as an optical thin film. The scales feature extremely large windows that enhance the scale reflectance, because the upper lamina of ridges and crossribs is very sparse. Characteristic for thin film reflectors, the spectral shape of the reflected light strongly depends on the angle of light incidence, shifting from pink to yellow when changing the angles of illumination and observation from normal to skew, and also the degree of polarization strongly varies. The simultaneous spectral and polarization changes serve a possibly widespread, highly effective communication system among butterflies for intraspecific communication during flight.

Some early history of replica techniques for electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1076-1077
Author(s):  
Robert M. Fisher
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Optical Microscope ◽  
Early History ◽  
Bulk Materials ◽  
Thin Sections ◽  
Transmission Electron ◽  
Reflected Light ◽  
History Of ◽  
Electron Microscopes

By 1940, a half dozen or so commercial or home-built transmission electron microscopes were in use for studies of the ultrastructure of matter. These operated at 30-60 kV and most pioneering microscopists were preoccupied with their search for electron transparent substrates to support dispersions of particulates or bacteria for TEM examination and did not contemplate studies of bulk materials. Metallurgist H. Mahl and other physical scientists, accustomed to examining etched, deformed or machined specimens by reflected light in the optical microscope, were also highly motivated to capitalize on the superior resolution of the electron microscope. Mahl originated several methods of preparing thin oxide or lacquer impressions of surfaces that were transparent in his 50 kV TEM. The utility of replication was recognized immediately and many variations on the theme, including two-step negative-positive replicas, soon appeared. Intense development of replica techniques slowed after 1955 but important advances still occur. The availability of 100 kV instruments, advent of thin film methods for metals and ceramics and microtoming of thin sections for biological specimens largely eliminated any need to resort to replicas.

scholarly journals Coloration principles of the Great purple emperor butterfly (Sasakia charonda)

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Doekele G. Stavenga ◽  
Hein L. Leertouwer ◽  
Kentaro Arikawa
Keyword(s):  
Thin Film ◽  
Light And Electron Microscopy ◽  
Film Properties ◽  
Microscopy Imaging ◽  
Orange Yellow ◽  
White Spots ◽  
Sasakia Charonda ◽  
Scale Types ◽  
Wing Scales ◽  
Optical Basis

AbstractThe dorsal wings of male Sasakia charonda butterflies display a striking blue iridescent coloration, which is accentuated by white, orange-yellow and red spots, as well as by brown margins. The ventral wings also have a variegated, but more subdued, pattern. We investigated the optical basis of the various colors of intact wings as well as isolated wing scales by applying light and electron microscopy, imaging scatterometry and (micro)spectrophotometry. The prominent blue iridescence is due to scales with tightly packed, multilayered ridges that contain melanin pigment. The scales in the brown wing margins also contain melanin. Pigments extracted from the orange-yellow and red spots indicate the presence of 3-OH-kynurenine and ommochrome pigment. The scales in the white spots also have multilayered ridges but lack pigment. The lower lamina of the scales plays a so-far undervalued but often crucial role. Its thin-film properties color the majority of the ventral wing scales, which are unpigmented and have large windows. The lower lamina acting as a thin-film reflector generally contributes to the reflectance of the various scale types.

scholarly journals Orientation-Dependent Reflection of Structurally Coloured Butterflies

Biomimetics ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 5
Author(s):  
Sigrid Zobl ◽  
Bodo D. Wilts ◽  
Willi Salvenmoser ◽  
Peter Pölt ◽  
Ille C. Gebeshuber ◽  
...  
Keyword(s):  
Orientation Dependence ◽  
Butterfly Species ◽  
Butterfly Wing ◽  
Step Size ◽  
Photonic Structures ◽  
Light Interference ◽  
Important Input ◽  
Individual Scale ◽  
The Individual ◽  
Wing Scales

The photonic structures of butterfly wing scales are widely known to cause angle-dependent colours by light interference with nanostructures present in the wing scales. Here, we quantify the relevance of the horizontal alignment of the butterfly wing scales on the wing. The orientation-dependent reflection was measured at four different azimuth angles, with a step size of 90°, for ten samples—two of different areas of the same species—of eight butterfly species of three subfamilies at constant angles of illumination and observation. For the observed species with varying optical structures, the wing typically exhibits higher orientation-dependent reflections than the individual scale. We find that the measured anisotropy is caused by the commonly observed grating structures that can be found on all butterfly wing scales, rather than the local photonic structures. Our results show that the technique employed here can be used to quickly evaluate the orientation-dependence of the reflection and hence provide important input for bio-inspired applications, e.g., to identify whether the respective structure is suitable as a template for nano-imprinting techniques.

Spectroscopy of Matrices and Thin Films with an Integrating Sphere

1989 ◽  
Vol 43 (2) ◽  
pp. 320-324 ◽  
Author(s):  
E. Berger ◽  
D. W. T. Griffith ◽  
G. Schuster ◽  
S. R. Wilson
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Experimental Approach ◽  
Matrix Isolation ◽  
Standard Theory ◽  
Integrating Sphere ◽  
Weak Absorption ◽  
Matrix Isolation Spectroscopy ◽  
Reflected Light ◽  
The Matrix

The paper describes a novel experimental approach to improving sensitivity to weak absorption in matrix isolation and thin film spectroscopy. The matrix or film is grown on the surface of an integrating sphere, in which the multiply reflected light correspondingly multipasses the sample film. The quantitative photometric behavior of the sphere is satisfactorily described by extending standard theory. Enhancement of absorption by a factor of at least 20 is possible and is demonstrated. The sphere has a number of useful advantages over other multipass techniques, particularly in matrix isolation spectroscopy.

scholarly journals Attractiveness of thermally different, uniformly black targets to horseflies: Tabanus tergestinus prefers sunlit warm shiny dark targets

2019 ◽  
Vol 6 (10) ◽  
pp. 191119 ◽  
Author(s):  
Gábor Horváth ◽  
Ádám Pereszlényi ◽  
Tímea Tóth ◽  
Szabolcs Polgár ◽  
Imre M. Jánosi
Keyword(s):  
Field Experiments ◽  
Elevated Temperatures ◽  
Thermal Characteristics ◽  
Optical Characteristics ◽  
Degree Of Polarization ◽  
Small Scale ◽  
Host Animal ◽  
Reflected Light ◽  
Scale Models ◽  
Imaging Polarimetry

From a large distance tabanid flies may find their host animal by means of its shape, size, motion, odour, radiance and degree of polarization of host-reflected light. After alighting on the host, tabanids may use their mechano-, thermo-, hygro- and chemoreceptors to sense the substrate characteristics. Female tabanids prefer to attack sunlit against shady dark host animals, or dark against bright hosts for a blood meal, the exact reasons for which are unknown. Since sunlit darker surfaces are warmer than shady ones or sunlit/shady brighter surfaces, the differences in surface temperatures of dark and bright as well as sunlit and shady hosts may partly explain their different attractiveness to tabanids. We tested this observed warmth preference in field experiments, where we compared the attractiveness to tabanids ( Tabanus tergestinus ) of a warm and a cold shiny black barrel imitating dark hosts with the same optical characteristics. Using imaging polarimetry, thermography and Schlieren imaging, we measured the optical and thermal characteristics of both barrels and their small-scale models. We recorded the number of landings on these targets and measured the time periods spent on them. Our study revealed that T. tergestinus tabanid flies prefer sunlit warm shiny black targets against sunlit or shady cold ones with the same optical characteristics. These results support our new hypothesis that a blood-seeking female tabanid prefers elevated temperatures, partly because her wing muscles are more rapid and her nervous system functions better (due to faster conduction velocities and synaptic transmission of signals) in a warmer microclimate, and thus, she can avoid the parasite-repelling reactions of host animals by a prompt take-off.

Microscale Radiative Effects in Complex Microstructures of Iridescent Butterfly Wing Scales

1997 ◽  
Vol 489 ◽  
Author(s):  
Haruna Tada ◽  
Seth E. Mann ◽  
Ioannis N. Miaoulis ◽  
Peter Y. Wong
Keyword(s):  
Thin Film ◽  
Numerical Modeling ◽  
Experimental Investigations ◽  
Butterfly Wing ◽  
Radiative Effects ◽  
Cellular Microstructure ◽  
Cellular Development ◽  
Optical Phenomena ◽  
Thin Film Interference ◽  
Wing Scales

AbstractThe cellular microstructure of insect scales can be detailed intricately with threedimensional structures and multiple thin-film layers. In butterflies, iridescent scales can reflect bright colors through thin-film interference and other optical phenomena; the balance of radiation is absorbed for thermoregulatory purposes. Results of numerical and experimental investigations into the function, properties, and structure of these scales are presented. Of particular interest are the numerical modeling of the microscale radiative effects in the scales, determining the optical properties of the biological material, and the cellular development of thin-film structures.

Rotating-Compensator Multichannel Ellipsometry: Applications in Process Development for Nanocrystalline Diamond Thin Films

1997 ◽  
Vol 502 ◽  
Author(s):  
R. W. Collins ◽  
Joungchel Lee ◽  
P. I. Rovira ◽  
Ilsin An
Keyword(s):  
Thin Film ◽  
Light Beam ◽  
Time Evolution ◽  
Film Growth ◽  
Nanocrystalline Diamond ◽  
Thin Film Growth ◽  
Degree Of Polarization ◽  
S Wave ◽  
Diamond Thin Film ◽  
New Instrument

ABSTRACTA multichannel spectroscopic ellipsometer based on the rotating-compensator principle was developed and applied to characterize nanocrystalline diamond thin film growth processes by plasma-enhanced chemical vapor deposition (PECVD). With the newly-designed instrument, a time resolution of 32 ms is possible for spectra (1.5˜4.0 eV) in the Stokes vector of the light beam reflected from the surface of the growing film. Several advantages of the rotating-compensator over the simpler rotating-polarizer multichannel ellipsometer design are demonstrated here for diamond thin film growth. These include the ability to: (i) resolve the sign ambiguity in the p–s wave phase-shift difference Δ, (ii) obtain accurate Δ values for low ellipticity polarization states, and (iii) deduce spectra in the degree of polarization of the light beam reflected from the film/substrate. The degree of polarization has been applied to characterize the time evolution of light scattering during the nucleation of the diamond, as well as the time evolution of thickness non-uniformity over the probed area of the growing film. In this paper, a brief description of calibration and data reduction for the new instrument is also provided.

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