Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals
Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals
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DOI：
10.1002/adfm.201603514
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发表时间：
2017-02-10
影响因子：
19
通讯作者：
Addadi, Lia
中科院分区：
文献类型：
--
作者：
Gur, Dvir;Palmer, Benjamin A.;Addadi, Lia
鸟嘌呤晶体在自然界中被广泛用于操控光。这篇专题文章的第一部分探索了生物如何通过改变鸟嘌呤晶体的大小、形态和排列来构建一系列非凡的光学“设备”，包括漫射散射器、宽带和窄带反射器、可调光子晶体和成像镜。第二部分概述了结晶鸟嘌呤的一些性质，以解释为什么这种材料非常适合这种光学应用。许多天然光学系统的高反射率最终源于鸟嘌呤晶体具有极高的折射率--这是由密集堆积的氢键层组成的各向异性晶体结构的产物。为了优化它们的反射率，许多生物对晶体的形态进行了精细的控制，形成了板状单晶，其中高折射率面优先表现出来。基于鸟嘌呤的光学材料广泛应用于伪装、显示和视觉等生物功能，并表现出一定程度的多功能性、可调性和复杂性，这是传统工程方法难以融入到人工设备中的。这些生物系统可能会激励下一代先进的光学材料。
Guanine crystals are widely used in nature to manipulate light. The first part of this feature article explores how organisms are able to construct an extraordinary array of optical "devices" including diffuse scatterers, broad-band and narrowband reflectors, tunable photonic crystals, and image-forming mirrors by varying the size, morphology, and arrangement of guanine crystals. The second part presents an overview of some of the properties of crystalline guanine to explain why this material is ideally suited for such optical applications. The high reflectivity of many natural optical systems ultimately derives from the fact that guanine crystals have an extremely high refractive index-a product of its anisotropic crystal structure comprised of densely stacked H-bonded layers. In order to optimize their reflectivity, many organisms exert exquisite control over the crystal morphology, forming plate-like single crystals in which the high refractive index face is preferentially expressed. Guanine-based optics are used in a wide range of biological functions such as in camouflage, display, and vision, and exhibit a degree of versatility, tunability, and complexity that is difficult to incorporate into artificial devices using conventional engineering approaches. These biological systems could inspire the next generation of advanced optical materials.