中南大学倪祥课题组和美国纽约城市大学先进科学研究中心Alù教授课题组、德国马普学会弗里茨哈伯研究所Paarmann教授课题组以及华中科技大学李培宁教授课题组合作，理论发现具有漏波特性且在特定方向传播的极化激元的存在，并通过激元显微镜和扫描近场光学成像等手段揭示了该极化激元的奇特的色散和具有高品质因子的传播特性。该工作发表在了Nature Communications上，倪祥教授为该工作的共同第一作者。

论文标题：

Observation of directional leaky polaritons at anisotropic crystal interfaces

论文摘要：

Extreme anisotropy in some polaritonic materials enables light propagation with a hyperbolic dispersion, leading to enhanced light-matter interactions and directional transport. However, these features are typically associated with large momenta that make them sensitive to loss and poorly accessible from far-field, being bound to the material interface or volume-confined in thin films. Here, we demonstrate a new form of directional polaritons, leaky in nature and featuring lenticular dispersion contours that are neither elliptical nor hyperbolic. We show that these interface modes are strongly hybridized with propagating bulk states, sustaining directional, long-range, sub-diffractive propagation at the interface. We observe these features using polariton spectroscopy, far-field probing and near-field imaging, revealing their peculiar dispersion, and – despite their leaky nature – long modal lifetime. Our leaky polaritons (LPs) nontrivially merge sub-diffractive polaritonics with diffractive photonics onto a unified platform, unveiling opportunities that stem from the interplay of extreme anisotropic responses and radiation leakage.

论文链接：

https://www.nature.com/articles/s41467-023-38326-7