当前位置: X-MOL 学术APL Photonics › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Hyperspectral topography of the twisted, cholesteric patterns of an insect cuticle under various conditions of helix obliquity
APL Photonics ( IF 5.6 ) Pub Date : 2020-09-04 , DOI: 10.1063/5.0019039
Aurélie Jullien 1 , Maxim Neradovskiy 1 , Michel Mitov 2
Affiliation  

Twisted cholesteric liquid crystal patterns are found in the iridescent chitin-containing cuticles of many insects. They may exhibit spatial variation in the helical pitch and in the orientation of the helix axis, as in the two-band, green and silver cuticle of the scarab beetle, Chrysina gloriosa, which is the focus of the present study. The silver bands are pattern-free, whereas the green bands exhibit an array of microcells. By hyperspectral microscopy with 6 nm spectral resolution in the range of 400 nm–1000 nm, we investigated the topography of twisted cuticular structures under various orientations of the helical axis, from an orientation close to the normal to the cuticle surface in the silver bands to a spatially varying orientation in the microcells. We deal with two aspects of the topography: the shape of the surface at the interface between the transparent wax layer and the chitin-protein matrix, which is a challenging task since the cuticle is covered by the wax layer preventing direct topographic measurements by standard techniques, and the features of the deep layers in the cuticle, by addressing the distribution of the helical pitch of the twisted structure at a variable depth. We demonstrate that both types of topographic information are embedded in the hyperspectral data. Specifically, we show that the spatial distribution of the spectral center of mass portrays the geometrical shape of the hexagonal microcells. Furthermore, we evidence the spectral signature of the structural patterns located at the edges of the microcells.

中文翻译:

螺旋倾角不同条件下昆虫表皮的扭曲胆甾型图案的高光谱地形

在许多昆虫的含虹彩甲壳质的表皮中发现了扭曲的胆甾型液晶图案。它们可能在螺旋间距和螺旋轴方向上表现出空间变化,例如在甲虫Chrysina gloriosa的两带,绿色和银色表皮中,这是本研究的重点。银色带没有图案,而绿色带则显示出一系列微孔。通过在400 nm至1000 nm范围内具有6 nm光谱分辨率的高光谱显微镜,我们研究了在螺旋轴的不同方向上扭曲的表皮结构的形貌,从接近银带中表皮表面的法线方向到微单元中空间上变化的方向。我们处理了地形的两个方面:透明蜡层和几丁质蛋白基质之间界面的表面形状,这是一项艰巨的任务,因为表皮被蜡层覆盖,无法通过标准技术进行直接的地形测量以及角质层深层的特征,通过解决在可变深度处扭曲结构的螺旋节距的分布。我们证明了两种类型的地形信息都嵌入在高光谱数据中。具体而言,我们表明质量频谱中心的空间分布描绘了六角形微细胞的几何形状。此外,我们证明了位于微细胞边缘的结构图案的光谱特征。
更新日期:2020-09-30
down
wechat
bug