Image polaritons in boron nitride for extreme polariton confinement with low losses
Image polaritons in boron nitride for extreme polariton confinement with low losses
复制标题
氮化硼中低损耗极端极化激元约束的图像极化激元
DOI：
10.1038/s41467-020-17424-w
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发表时间：
2020-07-20
影响因子：
16.6
通讯作者：
Oh, Sang-Hyun
中科院分区：
文献类型：
--
作者：
Lee, In-Ho;He, Mingze;Oh, Sang-Hyun
二维材料中的极化激元提供了金属等离子体难以实现的极端光限制。然而，这种紧密限制不可避免地增加了通过各种阻尼通道的光学损耗。在这里，我们证明了双曲声子极化激元在六方氮化硼可以克服这个基本的权衡。在两个观察到的极化激元模式，具有对称和反对称的电荷分布，后者表现出较低的光学损耗和更严格的极化激元限制。这种高动量模式的远场激发和检测成为可能，我们的谐振腔设计，可以提高耦合效率，通过虚拟极化激元模式与图像电荷，我们称之为“图像极化激元”。使用这些图像极化激元，我们实验观察到高达132和高达501的品质因数的创纪录的高有效指数。此外，我们的唯象理论表明，双曲表面散射的双曲声子极化激元的阻尼过程中的重要作用。二维材料中极化激元的严格限制导致光学损耗增加。在这里，作者展示了图像声子极化激元模式在六方氮化硼具有反对称电荷分布，其特征品质因子高达501和有效指数为132。
Polaritons in two-dimensional materials provide extreme light confinement that is difficult to achieve with metal plasmonics. However, such tight confinement inevitably increases optical losses through various damping channels. Here we demonstrate that hyperbolic phonon polaritons in hexagonal boron nitride can overcome this fundamental trade-off. Among two observed polariton modes, featuring a symmetric and antisymmetric charge distribution, the latter exhibits lower optical losses and tighter polariton confinement. Far-field excitation and detection of this high-momenta mode become possible with our resonator design that can boost the coupling efficiency via virtual polariton modes with image charges that we dub 'image polaritons'. Using these image polaritons, we experimentally observe a record-high effective index of up to 132 and quality factors as high as 501. Further, our phenomenological theory suggests an important role of hyperbolic surface scattering in the damping process of hyperbolic phonon polaritons. The tight confinement of polaritons in 2D materials leads to increased optical losses. Here, the authors demonstrate image phonon polariton modes in hexagonal boron nitride with an antisymmetric charge distribution that feature quality factors of up to 501 and an effective index of 132.