Polarized evanescent waves reveal trochoidal dichroism
Polarized evanescent waves reveal trochoidal dichroism
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DOI：
10.1073/pnas.2004169117
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发表时间：
2020-07-14
影响因子：
11.1
通讯作者：
Link, Stephan
中科院分区：
文献类型：
--
作者：
McCarthy, Lauren A.;Smith, Kyle W.;Link, Stephan
物质对光偏振的敏感性以线偏振和圆偏振效应为特征，分别对应于系统的各向异性和旋向性。最近的研究在近场特性的倏逝波揭示了偏振态与异相的横向和纵向振荡，导致在余摆线，或车轮，场运动。在这里，我们证明了物质对余摆线场方向的固有敏感性，并将这种性质命名为余摆线双色性。我们观察到的余摆线二向色性的差分激发成键和反键等离子体激元模式的两个耦合偶极散射体组成的系统。次摆线二向色性构成了对偏振灵敏度几何基础的观察，它与线性和圆二向色性有着根本的不同。它也可以用来表征分子系统，如某些捕光天线，在激发时具有侧手翻电荷运动。
Matter's sensitivity to light polarization is characterized by linear and circular polarization effects, corresponding to the system's anisotropy and handedness, respectively. Recent investigations in-to the near-field properties of evanescent waves have revealed polarization states with out-of-phase transverse and longitudinal oscillations, resulting in trochoidal, or cartwheeling, field motion. Here, we demonstrate matter's inherent sensitivity to the direc-tion of the trochoidal field and name this property trochoidal di-chroism. We observe trochoidal dichroism in the differential excitation of bonding and antibonding plasmon modes for a system composed of two coupled dipole scatterers. Trochoidal dichroism con-stitutes the observation of a geometric basis for polarization sensitiv-ity that fundamentally differs from linear and circular dichroism. It could also be used to characterize molecular systems, such as certain light-harvesting antennas, with cartwheeling charge motion upon excitation.