Transverse photon spin of bulk electromagnetic waves in bianisotropic media
Transverse photon spin of bulk electromagnetic waves in bianisotropic media
复制标题
双各向异性介质中体电磁波的横向光子自旋
DOI：
10.1038/s41566-019-0521-4
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发表时间：
2019-12-01
期刊：
影响因子：
35
通讯作者：
Zhang, Shuang
中科院分区：
文献类型：
--
作者：
Peng, Liang;Duan, Lingfu;Zhang, Shuang
光子具有自旋自由度，在光通信、信息处理和传感等领域有着重要的应用。在各向同性介质中，光子自旋与光的传播方向一致，遵循自旋动量锁定原理。有趣的是，远离界面衰减的表面波具有横向于其传播的光子自旋，为在受限系统中观察自旋相关激发提供了令人兴奋的机会。在这里，我们提出并实现了横向光子自旋（T自旋）在体介质中，而不依赖于任何接口的存在。通过在介质中引入双各向异性，我们给出了表面模的T自旋到体模的T自旋的映射。我们进一步发现，两个相反方向的双各向异性介质之间的界面支持与边缘相关的传播模式与可调的截止频率。我们的研究结果为操纵电磁波的自旋轨道相互作用提供了一个新的平台。
Photons possess spin degree of freedom, which plays an important role in various applications such as optical communications, information processing and sensing. In isotropic media, photon spin is aligned with the propagation direction of light, obeying the principle of spin momentum locking. Interestingly, surface waves decaying away from an interface have a photon spin transverse to its propagation, opening exciting opportunities for the observation of spin-dependent excitation in confined systems. Here, we propose and realize transverse photon spin (T-spin) in a bulk medium, without relying on the presence of any interfaces. We show the mapping of the T-spin of surface modes to that of the bulk modes by introducing bianisotropy into the medium. We further discover that the interface between two bianisotropic media of opposite orientations supports edge-dependent propagating modes with tunable cutoff frequencies. Our results provide a new platform for manipulating the spin-orbit interaction of electromagnetic waves.