Glass scales on the wing of the swordtail butterfly Graphium sarpedon act as thin film polarizing reflectors
Glass scales on the wing of the swordtail butterfly Graphium sarpedon act as thin film polarizing reflectors
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DOI：
10.1242/jeb.066902
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发表时间：
2012-02
影响因子：
2.8
通讯作者：
D. Stavenga;A. Matsushita;K. Arikawa;H. Leertouwer;B. Wilts
中科院分区：
文献类型：
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作者：
D. Stavenga;A. Matsushita;K. Arikawa;H. Leertouwer;B. Wilts
剑尾蝶的翅膀上有蓝色/绿色的斑块，下面覆盖着两种鳞片：白色鳞片和玻璃鳞片。透射电镜和扫描电镜显示白色鳞片具有典型的结构：具有突出脊状结构和大开窗的上层鳞片与平坦连续的下层鳞片被小梁很好地分开。在玻璃鳞片中，具有不明显的脊和窗的上层层几乎是平坦的，并与同样平坦的下层层紧密相对。因此，玻璃鳞片近似于理想的薄膜，这与它们定向反射光和虹彩的观察结果一致。用微分光光度计在玻璃尺度上测量的反射光谱和透射光谱与理想的非吸收薄膜计算的光谱一致。单片、隔离玻璃鳞片的成像散射测量表明，反射光可以被强偏振，表明它们具有偏振反射器的功能。
SUMMARY The wings of the swordtail butterfly Graphium sarpedon (the Common Bluebottle) have blue/green-colored patches that are covered on the underside by two types of scales: white and glass scales. Transmission and scanning electron microscopy revealed that the white scales are classically structured: the upper lamina, with prominent ridges and large open windows, is well separated by trabeculae from a flat, continuous lower lamina. In the glass scales, the upper lamina, with inconspicuous ridges and windows, is almost flat and closely apposed to the equally flat lower lamina. The glass scales thus approximate ideal thin films, in agreement with the observation that they reflect light directionally and are iridescent. Reflectance and transmittance spectra measured from the glass scales with a microspectrophotometer agree with spectra calculated for an ideal non-absorbing thin film. Imaging scatterometry of single, isolated glass scales demonstrated that the reflected light can be strongly polarized, indicating that they function as polarizing reflectors.