近日，华中科技大学陆培祥团队实现了操纵太赫兹声子偏振子在连续体中与束缚态的超强耦合状态。2025年10月9日出版的《光：科学与应用》杂志发表这项成果。

极性材料中光子和声子之间的强耦合产生了声子极化子，声子极化子封装了丰富的物理信息，为超快太赫兹强度和太赫兹光的拓扑工程提供了关键工具。然而，到目前为止，在超强耦合条件下形成和操纵太赫兹声子极化子仍然是一个很大的挑战。

研究组证明了声子(0.95THz)在MAPbI₃薄膜中和Au超表面中连续介质（BICs）中的金属束缚态。通过调整金超表面的尺寸、形状和周期等参数，可以使拉比分裂在声子频率的28%到48.4%之间连续调谐，达到超强耦合状态。通过引入小波变换，成功地提取了太赫兹声子偏振子的模式演化信息。结果表明，MAPbI₃薄膜的声子辐射强度随着耦合强度的增加而增强。这项工作不仅为太赫兹器件建立了一个新的平台，还为探索太赫兹声子极化子的复杂动力学开辟了新的途径。

附：英文原文

Title: Manipulating terahertz phonon-polariton in the ultrastrong coupling regime with bound states in the continuum

Author: Yang, Jiaxing, Zhang, Liyu, Wang, Kai, Zhang, Chen, Fan, Aoyu, He, Zijian, Li, Zhidi, Han, Xiaobo, Ling, Furi, Lu, Peixiang

Issue&Volume: 2025-10-09

Abstract: The strong coupling between photons and phonons in polar materials gives rise to phonon-polaritons that encapsulate a wealth of physical information, offering crucial tools for the ultrafast terahertz sources and the topological engineering of terahertz light. However, it is still quite challenging to form and manipulate the terahertz phonon-polaritons under the ultrastrong coupling regime till now. In this work, we demonstrate the ultrastrong coupling between the phonon (at 0.95THz) in a MAPbI3 film and the metallic bound states in the continuum (BICs) in Au metasurfaces. The Rabi splitting can be continuously tuned from 28% to 48.4% of the phonon frequency by adjusting the parameters (size, shape and period) of Au metasurfaces, reaching the ultrastrong coupling regime. By introducing wavelet transform, the mode evolution information of the terahertz phonon-polariton is successfully extracted. It indicates that the phonon radiation intensity of the MAPbI3 film is enhanced as the coupling strength is increased. This work not only establishes a new platform for terahertz devices but also opens new avenues for exploring the intricate dynamics of terahertz phonon-polaritons.

DOI: 10.1038/s41377-025-02044-0

Source: https://www.nature.com/articles/s41377-025-02044-0