Computational Physics, Zernike Institute for Advanced Materials, University of Groningen, Groningen, NL9747AG, The Netherlands.
J Exp Biol. 2012 Feb 15;215(Pt 4):657-62. doi: 10.1242/jeb.066902.
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.
剑尾鱼蛱蝶 Graphium sarpedon（普通蓝瓶）的翅膀上有蓝色/绿色的斑块，这些斑块的下侧覆盖着两种鳞片：白色鳞片和玻璃鳞片。透射电子显微镜和扫描电子显微镜显示，白色鳞片具有经典的结构：上层鳞片有明显的脊和大的开口窗，由小梁很好地与平坦的连续下层鳞片隔开。在玻璃鳞片中，上层鳞片几乎是平坦的，与同样平坦的下层鳞片紧密贴合，且不明显的脊和窗口。因此，玻璃鳞片近似于理想的薄膜，这与它们定向反射光且具有虹彩的观察结果一致。使用微分光光度计从玻璃鳞片上测量的反射率和透射率光谱与为理想非吸收性薄膜计算的光谱一致。对单个孤立的玻璃鳞片的成像散射测量表明，反射光可以强烈偏振，表明它们作为偏振反射器发挥作用。
