Strong Spin-Orbit Interaction of Light in Plasmonic Nanostructures and Nanocircuits
Strong Spin-Orbit Interaction of Light in Plasmonic Nanostructures and Nanocircuits
复制标题
等离激元纳米结构和纳米电路中光的强自旋轨道相互作用
DOI：
10.1103/physrevlett.117.166803
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发表时间：
2016-10-12
影响因子：
8.6
通讯作者：
Xu, Hongxing
中科院分区：
文献类型：
--
作者：
Pan, Deng;Wei, Hong;Xu, Hongxing
光子的自旋自由度和轨道自由度之间的耦合通常非常弱，但最近的研究表明，这种自旋轨道相互作用（SOI）可以很容易地在金属结构中检测到。在这里，我们展示了光的SOI在等离子体金属纳米结构中是如何增强的，探索了这种效应的潜在机制，并进一步展示了如何将其潜在地用于纳米光子应用。具体来说，我们证明了圆偏振光子被单个金属纳米球散射导致光沿着纳米球附近急剧扭曲的手性轨迹传播，从而揭示了表面等离子体近场的强SOI。在金属纳米线尖端产生的表面等离子体的近场中，我们也发现了由强SOI诱导的类似自旋依赖的光轨迹。我们利用这种强SOI首次实验实现了紧凑等离子体纳米电路中光子的自旋分选。这些发现为如何在等离子体纳米电路和未来的自旋控制纳米光子器件中增强光的SOI和探索新的自由度提供了见解。
The coupling between the spin and orbital degrees of freedom of photons is usually very weak, but recent studies have shown that this spin-orbit interaction (SOI) can be easily detected in metal structures. Here we show how the SOI of light is enhanced in plasmonic metal nanostructures, explore the underlying mechanism for this effect, and further demonstrate how it could potentially be harnessed for nanophotonic applications. Specifically, we show that the scattering of circularly polarized photons by a single metal nanosphere causes light to propagate along sharply twisted chiral trajectories near the nanosphere, thus revealing a strong SOI in the near field of surface plasmons. We find similar spin-dependent trajectories of light induced by a strong SOI also in the near field of surface plasmons generated on the tip of a metal nanowire. We utilize this strong SOI to for the first time experimentally realize spin sorting of photons in a compact plasmonic nanocircuit. The findings offer insights into how the SOI of light can be enhanced and explored for a new degree of freedom in plasmonic nanocircuits and future spin-controlled nanophotonic devices.