Active Plasmonics and Active Chiral Plasmonics through Orientation-Dependent Multipolar Interactions
Active Plasmonics and Active Chiral Plasmonics through Orientation-Dependent Multipolar Interactions
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DOI：
10.1021/acsnano.0c03971
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发表时间：
2020-09-22
期刊：
影响因子：
17.1
通讯作者：
Shumaker-Parry，Jennifer S.
中科院分区：
文献类型：
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作者：
Stevenson，Peter R.;Du，Matthew;Shumaker-Parry，Jennifer S.
虽然大多数主动等离子体的努力集中在响应超材料调制光学响应，我们提出了一个简单的替代方案的基础上应用方向控制，可能会实现许多被动等离子体材料。被动等离子体基序更容易制备，但不能在制造后改变。我们表明，这样的系统可以很容易地操纵通过基板取向控制，以产生主动等离子体激元和主动手性等离子体激元响应。使用金纳米新月作为我们的模型平台，我们展示了在相对于垂直入射的斜入射下，光学消光从-21%到+36%的调谐。还证明了衬底取向相对于入射偏振的变化可控制地切换手旋手性（例如，Δg= ± 0.55）。这些主动等离子体激元响应起因于共振模式的多极特性。特别是，我们相关的磁电和偶极-四极极化率与不同的轻物质的取向依赖在近场和远场局部表面等离子体激元活动。此外，远场光学响应对高阶多极子的归因突出了这些依赖于取向的表征技术提供的灵敏度，以探测局部电磁场梯度对等离子体响应的影响。通过在等离子体激元和手性等离子体激元响应中表现出不可预测的结构纳米尺度变化（例如，左尖端和右尖端不对称性）不能通过形貌成像物理分辨。
While most active plasmonic efforts focus on responsive metamaterials to modulate optical response, we present a simple alternative based on applied orientation control that can likely be implemented for many passive plasmonic materials. Passive plasmonic motifs are simpler to prepare but cannot be altered postfabrication. We show that such systems can be easily manipulated through substrate orientation control to generate both active plasmonic and active chiral plasmonic responses. Using gold nanocrescents as our model platform, we demonstrate tuning of optical extinction from −21% to +36% at oblique incidence relative to normal incidence. Variation of substrate orientation in relation to incident polarization is also demonstrated to controllably switch chiroptical handedness (e.g., Δg= ± 0.55). These active plasmonic responses arise from the multipolar character of resonant modes. In particular, we correlate magnetoelectric and dipole–quadrupole polarizabilities with different light-matter orientation-dependence in both near- and far-field localized surface plasmon activity. Additionally, the attribution of far-field optical response to higher-order multipoles highlights the sensitivity offered by these orientation-dependent characterization techniques to probe the influence of localized electromagnetic field gradients on a plasmonic response. The sensitivity afforded by orientation-dependent optical characterization is further observed by the manifestation in both plasmon and chiral plasmon responses of unpredicted structural nanocrescent variance (e.g., left- and right-tip asymmetry) not physically resolved through topographical imaging.