Yang Qingdong, Wen Xinhua, Li Zhongfu, You Oubo, Zhang Shuang
New Cornerstone Science Laboratory, Department of Physics, University of Hong Kong, 999077, Hong Kong, China.
Department of Electrical & Electronic Engineering, University of Hong Kong, 999077, Hong Kong, China.
Nat Commun. 2025 Jan 2;16(1):151. doi: 10.1038/s41467-024-55159-0.
Tellegen medium has long been a topic of debate, with its existence being contested over several decades. It was first proposed by Tellegen in 1948 and is characterized by a real-valued cross coupling between electric and magnetic responses, distinguishing it from the well-known chiral medium that has imaginary coupling coefficients. Significantly, Tellegen responses are closely linked to axion dynamics, an extensively studied subject in condensed matter physics. Here, we report the realization of Tellegen metamaterials in the microwave region through a judicious combination of subwavelength metallic resonators, gyromagnetic materials, and permanent magnets. We observe the key signature of the Tellegen response - a Kerr rotation for reflected wave, while the polarization remains the same in the transmission direction. The retrieved effective Tellegen parameter is several orders of magnitude greater than that of natural materials. Our work opens door to a variety of nonreciprocal photonic devices and may provide a platform for studying axion physics.
泰勒根媒质长期以来一直是一个争论的话题，其存在在几十年间一直备受争议。它最初由泰勒根于1948年提出，其特点是电响应和磁响应之间存在实值交叉耦合，这使其有别于具有虚数耦合系数的著名手性媒质。值得注意的是，泰勒根响应与轴子动力学密切相关，轴子动力学是凝聚态物理中一个被广泛研究的课题。在此，我们报告通过亚波长金属谐振器、旋磁材料和永磁体的明智组合，在微波区域实现了泰勒根超材料。我们观察到了泰勒根响应的关键特征——反射波的克尔旋转，而在传输方向上偏振保持不变。所提取的有效泰勒根参数比天然材料的参数大几个数量级。我们的工作为各种非互易光子器件打开了大门，并可能为研究轴子物理提供一个平台。
