Enantioselective Optical Trapping of Chiral Nanoparticles with Plasmonic Tweezers
Enantioselective Optical Trapping of Chiral Nanoparticles with Plasmonic Tweezers
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DOI：
10.1021/acsphotonics.5b00574
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发表时间：
2016-03-01
期刊：
影响因子：
7
通讯作者：
Dionne, Jennifer A.
中科院分区：
文献类型：
--
作者：
Zhao, Yang;Saleh, Amr A. E.;Dionne, Jennifer A.
对映体分离是许多化学合成中的关键步骤，特别是对于药物而言，但流行的化学方法仍然效率低下。在这里，我们介绍了一种使用同轴等离子体孔径对手性样本进行分类的光学技术。这些孔径由嵌入银中的深亚波长二氧化硅通道组成，可以稳定地捕获亚 20 nm 介电纳米颗粒。通过全场模拟和分析计算，我们表明可以通过圆偏振照明实现对映异构体的选择性捕获。相反的对映体在符号和大小上都会经历不同的捕获力：一种被困在深势阱中，而另一种则被势垒排斥。这些电势在一系列手性极化率和对映体孔径分离中保持相反的符号。我们的理论表明，手性光和手性样品的相互作用可以通过非手性等离子体孔径介导，为全光学对映体纯合成提供了可能的途径。
Enantiomer separation is a critical step in many chemical syntheses, particularly for pharmaceuticals, but prevailing chemical methods remain inefficient. Here, we introduce an optical technique to sort chiral specimens using coaxial plasmonic apertures. These apertures are composed of a deeply subwavelength silica channel embedded in silver and can stably trap sub-20 nm dielectric nanoparticles. Using both full-field simulations and analytic calculations, we show that selective trapping of enantiomers can be achieved with circularly polarized illumination. Opposite enantiomers experience distinct trapping forces in both sign and magnitude: one is trapped in a deep potential well, while the other is repelled with a potential barrier. These potentials maintain opposite signs across a range of chiral polarizabilities and enantiomer-aperture separations. Our theory indicates that the interaction of chiral light and chiral specimens can be mediated by achiral plasmonic apertures, providing a possible route toward all-optical enantiopure syntheses.