High-fidelity spherical cholesteric liquid crystal Bragg reflectors generating unclonable patterns for secure authentication.
High-fidelity spherical cholesteric liquid crystal Bragg reflectors generating unclonable patterns for secure authentication.
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DOI：
10.1038/srep26840
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发表时间：
2016-05-27
影响因子：
4.6
通讯作者：
Lagerwall JP
中科院分区：
文献类型：
--
作者：
Geng Y;Noh J;Drevensek-Olenik I;Rupp R;Lenzini G;Lagerwall JP
单分散的双折射液晶微球表现出球对称的布拉格反射，通过光子交叉通信产生动态可调谐的多色图案。这些图案由特定的球体排列唯一地限定，可以使纳米微球在无数安全应用中非常有用，作为识别和认证其载体（主要是物理对象或人）的标签。然而，迄今为止研究的微滴的光学质量是不令人满意的，特别是在聚合之后，这是获得可用于物体识别的耐用样品所需的步骤。我们表明，从液滴到壳的过渡解决了所有关键问题，即使在聚合后也能产生清晰的图案和优异的光学质量，聚合后的壳保持相当大的机械变形。此外，我们证明，与先前的预期相反，交叉通信甚至发生在不相同的外壳之间。这打开了额外的通信渠道，大大增加了生成的模式的复杂性和独特性。
Monodisperse cholesteric liquid crystal microspheres exhibit spherically symmetric Bragg reflection, generating, via photonic cross communication, dynamically tuneable multi-coloured patterns. These patterns, uniquely defined by the particular sphere arrangement, could render cholesteric microspheres very useful in countless security applications, as tags to identify and authenticate their carriers, mainly physical objects or persons. However, the optical quality of the cholesteric droplets studied so far is unsatisfactory, especially after polymerisation, a step required for obtaining durable samples that can be used for object identification. We show that a transition from droplets to shells solves all key problems, giving rise to sharp patterns and excellent optical quality even after polymerisation, the polymerised shells sustaining considerable mechanical deformation. Moreover, we demonstrate that, counter to prior expectation, cross communication takes place even between non-identical shells. This opens additional communication channels that add significantly to the complexity and unique character of the generated patterns.