论文标题
使用快速电子的单轴材料中的探测和转向散装和表面声子极化子：六角硼
Probing and steering bulk and surface phonon polaritons in uniaxial materials using fast electrons: hexagonal boron nitride
论文作者
论文摘要
从理论上讲，我们通过分析电子能量损耗（EEL）光谱来描述单轴材料中的电子夫妇对偏光元模式的速度。我们表明，在具有双曲色散的单轴介质的情况下，可以通过快速的电子穿过体积或材料和真空之间的无限界面来激发散装和表面模式。有趣的是，与各向同性材料的激发相反，在单轴介质外行驶的快速电子可以激发大量模式。我们用代表性的单轴材料六角硼硝化物证明了我们的发现。我们表明，散装和表面声子极化模式的激发与电子速度密切相关，并且高度依赖于电子束轨迹和材料的光轴之间的角度。我们的工作提供了一项系统的研究，以理解双曲线材料中快速电子束激发的散装和表面极化子，并为通过改变电子速度及其方向而设定了一种方法来引导和控制极性波的传播。
We theoretically describe how fast electrons couple to polaritonic modes in uniaxial materials by analyzing the electron energy loss (EEL) spectra. We show that in the case of an uniaxial medium with hyperbolic dispersion, bulk and surface modes can be excited by a fast electron traveling through the volume or along an infinite interface between the material and vacuum. Interestingly, and in contrast to the excitations in isotropic materials, bulk modes can be excited by fast electrons traveling outside the uniaxial medium. We demonstrate our findings with the representative uniaxial material hexagonal boron nitride. We show that the excitation of bulk and surface phonon polariton modes is strongly related to the electron velocity and highly dependent on the angle between the electron beam trajectory and the optical axis of the material. Our work provides a systematic study for understanding bulk and surface polaritons excited by a fast electron beam in hyperbolic materials and sets a way to steer and control the propagation of the polaritonic waves by changing the electron velocity and its direction.
