Nanometer-Scale Spatial and Spectral Mapping of Exciton Polaritons in Structured Plasmonic Cavities
Nanometer-Scale Spatial and Spectral Mapping of Exciton Polaritons in Structured Plasmonic Cavities
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DOI：
10.1103/physrevlett.128.197401
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发表时间：
2022-05-12
影响因子：
8.6
通讯作者：
Masiello, David J.
中科院分区：
文献类型：
--
作者：
Bourgeois, Marc R.;Beutler, Elliot K.;Masiello, David J.
激子极化激元（EP）是一种普遍存在的光物质激发态，作为基础物理的实验平台和全光计算的组成部分，受到广泛的研究。由于其独特的属性和容易的实验可调性，EP可能使强非线性，凝聚，和超流在室温下。然而，光的衍射极限和快速电子探针的动量含量排除了在纳米级结构的腔中表现出能量-动量分散的EP的表征。在这里，我们提出了完全相对论分析理论和同伴的数值模拟表明，这些限制可以克服测量EP在周期性纳米光子腔的自然能量，动量和长度尺度通过晶格电子能量增益谱。结合光的高动量分辨率和聚焦电子束的纳米级空间分辨率，晶格电子能量增益谱可以使用目前可用的单色、像差校正的扫描透射电子显微镜来曝光深亚波长EP特征。
Exciton polaritons (EPs) are ubiquitous light-matter excitations under intense investigation as test beds of fundamental physics and as components for all-optical computing. Owing to their unique attributes and facile experimental tunability, EPs potentially enable strong nonlinearities, condensation, and superfluidity at room temperature. However, the diffraction limit of light and the momentum content of fast electron probes preclude the characterization of EPs in nanoscale structured cavities exhibiting energy-momentum dispersion. Here we present fully relativistic analytical theory and companion numerical simulations showing that these limitations can be overcome to measure EPs in periodic nanophotonic cavities on their natural energy, momentum, and length scales via lattice electron energy gain spectroscopy. With the combined high momentum resolution of light and nanoscale spatial resolution of focused electron beams, lattice electron energy gain spectroscopy can expose deeply subwavelength EP features using currently available monochromated, aberration-corrected scanning transmission electron microscopes.