论文标题
扭曲的纳米镜：用扭曲的声子在纳米级处操纵光线
Twisted Nano-optics: Manipulating Light at the Nanoscale with Twisted Phonon Polaritonic Slabs
论文作者
论文摘要
最近的发现表明，当两层范德华（VDW）材料叠加在其各自的平面内主轴之间的相对扭角时，耦合系统的电子性能可以显着改变。在这里，我们证明可以将类似的概念扩展到光学领域，尤其是在传播偏光子，混合光 - 摩擦相互作用的过程中。为此，我们制造了由两个支撑低损失各向异性声子极性子（PHP）的极性VDW晶体（MOO3）的扭曲平板组成的堆栈，并在局部化源（金属天线）发射时对后者的传播进行图像。我们的图像表明，在临界角度下，PHPS同源曲线（确定固定频率的PHPS动量）会发生拓扑跃迁。值得注意的是，在这个角度，pHP的传播沿预定方向（流管状态）强烈引导，而没有几何扩散（无衍射）。这些结果证明了一种新的自由度（扭曲角），用于控制纳米级极化子的传播，具有纳米成像，（BIO）传感，量子应用和热量管理的潜力。
Recent discoveries have shown that when two layers of van der Waals (vdW) materials are superimposed with a relative twist angle between their respective in-plane principal axes, the electronic properties of the coupled system can be dramatically altered. Here, we demonstrate that a similar concept can be extended to the optics realm, particularly to propagating polaritons, hybrid light-matter interactions. To do this, we fabricate stacks composed of two twisted slabs of a polar vdW crystal (MoO3) supporting low-loss anisotropic phonon polaritons (PhPs), and image the propagation of the latter when launched by localized sources (metal antennas). Our images reveal that under a critical angle the PhPs isofrequency curve (determining the PhPs momentum at a fixed frequency) undergoes a topological transition. Remarkably, at this angle, the propagation of PhPs is strongly guided along predetermined directions (canalization regime) with no geometrical spreading (diffraction-less). These results demonstrate a new degree of freedom (twist angle) for controlling the propagation of polaritons at the nanoscale with potential for nano-imaging, (bio)-sensing, quantum applications and heat management.
