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| 对称破缺导致的自旋霍尔效应研究 |
| The spin Hall effect induced by symmetry breaking |
| 投稿时间:2025-01-15 |
| DOI:10.3969/j.issn.1005-5630.202501150007 |
| 中文关键词: 对称破缺 紧聚焦 自旋角动量局域化 |
| 英文关键词:symmetry breaking tight focusing localization of spin angular momentum |
| 基金项目:上海市自然科学基金(21ZR1443800) |
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| 中文摘要: |
| 本文详细研究了紧聚焦条件下,径向偏振涡旋光引入对称破缺后所诱发的自旋霍尔效应。当光束不携带涡旋相位时,研究结果表明,对称破缺的引入不仅导致焦斑光强、相位及偏振态分布发生显著改变,更使焦斑分裂为沿中心对称轴分布的两个子斑。此时偏振态由初始的径向分布转变为椭圆杂化分布,促使纵向自旋角动量呈现显著局域化特征(即自旋霍尔效应),而横向自旋角动量的局域化程度则相对弱化。当光束携带涡旋相位后,对称破缺会引发焦斑光强的偏心分布特征,且该现象随拓扑荷数增大而呈现增强趋势。横向自旋角动量的x分量局域化程度在此条件下减弱,而y分量局域化程度却得到显著增强。研究表明,对称破缺通过促使电场右旋分量分布更加集中,不仅增强了自旋霍尔效应,也使纵向自旋角动量的谷值增大。本研究成果以期为深入理解紧聚焦光场中自旋轨道相互作用提供新的理论视角。 |
| 英文摘要: |
| This study systematically investigates the spin Hall effect induced by symmetry breaking in tightly focused radially polarized vortex beams. For beams without a vortex phase, the results demonstrate that the introduction of symmetry breaking not only significantly alters the intensity, phase, and polarization distributions of the focal spot but also splits the focal spot into two sub-spots symmetrically distributed along the central axis. The polarization state transitions from an initial radial distribution to an elliptically hybridized distribution, leading to pronounced localization of the longitudinal spin angular momentum (i.e., the spin Hall effect), while the localization degree of the transverse spin angular momentum is weakened. When a vortex phase is incorporated, symmetry breaking induces an eccentric intensity distribution in the focal spot, with this phenomenon intensifying as the topological charge increases. Notably, the localization of the x-component of the transverse spin angular momentum is reduced under these conditions, whereas the y-component exhibits enhanced localization. Further analysis reveals that symmetry breaking promotes a more concentrated distribution of the right-handed circularly polarized electric field component, thereby amplifying the spin Hall effect and increasing the valley depth of the longitudinal spin angular momentum. The findings aim to provide novel theoretical insights into spin-orbit interactions in tightly focused optical fields. |
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