AI 中文总结
研究揭示皇家宝石蝴蝶的背翅鳞片含单金刚石结构，其3-4个晶胞的设计实现与角度无关的蓝色，经双光子聚合人工复现红外光学响应，为相关光子器件开辟新路径。
AI 中文摘要
具有窄光谱光子带宽和高反射率的结构色对于现代光学应用（包括显示器、激光系统和光学传感等）至关重要。实现这种与角度无关的着色通常依赖于多晶或固有结构无序，但要在角度均匀性、高亮度和强色彩对比度之间取得平衡仍具挑战性。本文揭示了蓝宝石般的皇家宝石蝴蝶（Hypochrysops polycletus）呈现出鲜艳、与角度无关的蓝色的结构起源。三维（3D）电子显微镜显示，其背翅鳞片具有单金刚石结构，这是一种此前仅在甲虫和象鼻虫中记录到的三维光子晶体。晶体畴形成了特殊的类正弦表面几何结构，具有明显的模板形态引导排列。与通常支持多个高对称禁带的更厚生物光子结构不同，该设计在传播方向上仅包含3-4个晶胞。其光学响应由基频禁带主导，存在两种主要散射机制：分层结构{111}倾斜侧壁的镜面反射，以及由强各向异性布洛赫输运实现的局域类法向模式的汇聚。通过双光子聚合模拟这些特征，我们在红外区域人工复现了该光学响应。该研究为受生物启发的明亮漫反射着色和角度鲁棒光子器件开辟了一条途径。
英文摘要
Structural colouration with narrow spectral photonic bandwidth and high reflectivity is of critical importance for modern optical applications, including displays, laser systems, and optical sensing, etc. Achieving such angle independent colouration typically relies on polycrystalline or inherent structural disorder. However, balancing angular uniformity with high brightness and strong colour contrast remains challenging. Herein, we uncover the structural origin of the spectacular bright, angle-independent blue colouration of Hypochrysops polycletus, a sapphire-like Royal Jewel butterfly. Three-dimensional (3D) electron microscopy reveals that the dorsal wing scale has a single diamond structure, a 3D photonic crystal previously documented only in beetles and weevils. The crystal domains form an extraordinary quasi sinusoidal surface geometry with a distinct template morphology-guided arrangement. Unlike typically thicker biophotonic structures that support multiple high symmetry stopbands, this design contains only 3-4 unit cells in the propagation direction. Its optical response is dominated by the fundamental stopband, with two dominant scattering mechanisms: specular reflection at the {111} inclined sidewalls of the hierarchical structure, and funnelling into localised quasi-normal modes enabled by a strongly anisotropic Bloch transport. By mimicking these features with two-photon polymerisation, we artificially reproduced the optical response in the infrared region. The study opens a pathway towards bioinspired brilliant diffuse colouration and angle-robust photonic devices.
