The vivid color of beetles can affect future light technology

When studying vivid green and red on a beetle, scientists have discovered that the cause of the spectral reflection in these beetles is due to defects in the structure of their hard shells.

Understanding how this structure produces colorful colors can help scientists design chiral reflectors that are chiral for use in laser technology and future displays. (Chiral words because the Greek word ' cheir ' means hand. Our hands are chiral (hand symmetry): the hand is the image of the left hand through the mirror. but without the same space structure (right hand cannot fit into the left glove).

With more than 30,000 species of beetle beetles that live all over the world, the scientists studied are Gymnopleurus virens , the beetle found primarily in South America. In the early 1990s, scientists discovered that this beetle reflects most of the light on the left hand (light is polarized around the left) and hardly reflects light. on the right - this is a unique case known about this phenomenon in nature.

These beetle beetles have defects in the structure of the class
Hard shells and this has made them colorful. (Photo: Brink, et al)

Decades later, scientists discovered the cause of this asymmetry priority. The hard beetle's shell consists of several layers of microfiber arranged parallel to each other, giving priority to the polarized light along the direction of these fibers. Each layer rotates a bit in proportion to the upper layer, forming a helical stack facing in the left direction. The arrangement of these layers reflects the polarized light around the left and this can be clearly seen thanks to the spiral shape of the waves rotating around each other in the left direction.

'Why does nature give hard-winged beetles the nature of reflecting this light on the left, which is a difficult question,' said scientist Johan Brink, a member of the recent team on This phenomenon, said. 'Colors in insects are usually some sort of compromise between camouflage and efforts to find their mates. In some cases (usually with yellow, black and red), it is a warning to predators that they are poisonous. My feeling is that these beetles are trying to make them easier to see by expanding the reflection range. However, at this time, this is just an opinion that has not been proven deeply. '

The photo taken with an electron scanning microscope shows the cross-section of a hard shell of a green beetle.The right white line marks the point where the distance between the yarn layers increases by 10%.(Photo: Brink, et al)

Together with Brink, scientists Nick van der Berg and Linda Prinsloo from the University of Pretoria, South America and Ian Hodgkinson from the University of Otaga, New Zealand explained why the beetles have this unusual light color. there is a very large reflectance spectrum, which is different from the flat and less luminous spectrum of other beetles.

'From the inadequate combination of measured spectral calculations and calculations based on the perfect chiral structure, we suspected that there must be something' unstable 'in the structure. shell of these bugs. By trial and error, we discovered that we can reproduce the spectra almost exactly by acknowledging some of the failures in the arrangement of the layers of fibers in their shells. Only when we had the idea of ​​finding something, did we discover exactly how these beetles did this 'trick'.

By projecting light on the beetle's hard shells and reflecting light reflection, scientists have observed puzzling modifications in the spectrum, showing the existence of turbulence in the Screw surface layer in their hard shell.

Using electron scanning microscopy, the team discovered this interesting defect: that while at first sight the microscopic layers seemed to be evenly spaced, scientists identified a The point where the distance between classes changes dramatically about 10% at micrometre. According to the scientists' model, this cycle defect has expanded the reflectance range by up to 4 times the width obtained from a perfect screw face.

Scientists also study why some beetles are red while others are blue . If it is assumed that both different properties have the same material, the only difference lies in different thicknesses in the fiber layers in their hard shell. Another explanation is that the different colors on each bug are hard - for example, the green edge on a red bug or the blue edge on a green eyebrow is a tree - appearing when the corner falling.

'We suspect that the blue ones grow slightly slower, probably due to the more arid conditions,' Brink said. 'Reds are found mainly in the wetter (and greener) areas, where they grow faster and produce more thick layers. This, therefore, is closely related to the idea that their colorful colors are making them easier to see. '

Scientists also said that understanding how nature's 'imperfect' fabrication highlights the optical properties of beetles can provide applications for technology. laser and display.

'Potential applications of this kind of' defect fabrication ', can be wideband laser reflectors for semiconductor laser devices and narrow band-tip sharpeners that are sometimes used in spectra. learn to identify and classify materials and minerals, ' explained Brink.

Thanh Van