近日，西班牙奥维耶多大学P. Alonso-González团队研究了纳米尺度上双曲极化与有机分子之间的定向强耦合。相关论文于2025年9月22日发表在《自然—光子学》杂志上。

强耦合是物理学中的一个基本概念，描述光与物质之间的极端相互作用。最近的实验表明，在纳米尺度上存在强耦合，其中强约束的极化子而不是光子与量子发射器或分子振动耦合。与后者的耦合通常被称为振动强耦合（VSC），它具有重要的基础和技术意义，因为它可以成为修饰分子性质的有效工具。然而，VSC的实现，特别是在纳米尺度上，依赖于调谐机制的发展，这种调谐机制实现了控制耦合强度，并最终控制其方向性，为特定分子振动的选择性耦合打开大门。

研究组报告了在纳米尺度上进行的定向VSC的观察。具体地说，研究组展示了与五苯分子耦合的双曲声子极化子传播的纳米级图像，揭示了VSC传播极化子的指纹-振动共振时色散的显著抗交叉-可以作为传播方向的函数进行调制。此外，研究组还证明了VSC可以表现出薄分子层的最佳条件，其特征是沿单一方向的耦合强度最大。这种现象是通过分析极化场与不同厚度的分子层的重叠来理解的。除了具有重要的基础意义外，该发现还有望在纳米尺度上用于定向传感或局部化学性质定向控制。

附：英文原文

Title: Directional strong coupling at the nanoscale between hyperbolic polaritons and organic molecules

Author: F. Tresguerres-Mata, A. I., Matveeva, O. G., Lanza, C., lvarez-Cuervo, J., Voronin, K. V., Calavalle, F., Avedissian, G., Daz-Nez, P., lvarez-Prez, G., Tarazaga Martn-Luengo, A., Taboada-Gutirrez, J., Duan, J., Martn-Snchez, J., Bylinkin, A., Hillenbrand, R., Mishchenko, A., Hueso, Luis E., Volkov, V. S., Nikitin, A. Y., Alonso-Gonzlez, P.

Issue&Volume: 2025-09-22

Abstract: Strong coupling is a fundamental concept in physics that describes extreme interactions between light and matter. Recent experiments have demonstrated strong coupling at the nanometre scale, where strongly confined polaritons, rather than photons, couple to quantum emitters or molecular vibrations. Coupling with the latter is generally referred to as vibrational strong coupling (VSC) and is of substantial fundamental and technological interest, as it can be an effective tool for modifying molecular properties. However, the implementation of VSC, especially at the nanoscale, depends on the development of tuning mechanisms that allow control over the coupling strength and, eventually, its directionality, opening the door for the selective coupling of specific molecular vibrations. Here we report the observation of directional VSC, which we carried out at the nanoscale. Specifically, we show the nanoscale images of propagating hyperbolic phonon polaritons coupled to pentacene molecules, revealing that the fingerprint of VSC for propagating polaritons—a marked anticrossing in their dispersion at the vibrational resonance—can be modulated as a function of the direction of propagation. In addition, we show that VSC can exhibit an optimal condition for thin molecular layers, characterized by the maximum coupling strength along a single direction. This phenomenon is understood by analysing the overlap of the polariton field with molecular layers of varying thicknesses. Apart from their fundamental importance, our findings promise novel applications for directional sensing or local directional control of chemical properties at the nanoscale.

DOI: 10.1038/s41566-025-01762-6

Source: https://www.nature.com/articles/s41566-025-01762-6