论文标题
扭曲的范德华双层中拓扑偏振子和光子魔法角度的观察
Observation of topological polaritons and photonic magic angles in twisted van der Waals bi-layers
论文作者
论文摘要
扭曲的二维双层通过层间旋转和耦合对电子带的精致控制，从而实现了魔法 - 角平面超导性和Moiré型激子。在这里，我们证明了如何与大型各向异性结合使用，可以极端控制和操纵范德华（VDW）双层中的声子极化子（PHP）的光子分散体。我们在实验上观察到可调的拓扑转变，从开放式（双曲线）到闭合的（椭圆形的）色散轮廓，在光子魔法角度在光子魔术角处，由Polariton杂交引起，并由拓扑数量强构控制。在这些过渡时，双层色散表现出低损失的可调式载体量和无衍射传播，分辨率低于λ0/40。我们的发现将Twistronics和MoiréPhysics扩展到纳米光子学和偏光型，具有巨大的纳米成像，纳米级光传播，能量转移和量子应用的潜力。
Twisted two-dimensional bi-layers offer exquisite control on the electronic bandstructure through the interlayer rotation and coupling, enabling magic-angle flat-band superconductivity and moiré excitons. Here, we demonstrate how analogous principles, combined with large anisotropy, enable extreme control and manipulation of the photonic dispersion of phonon polaritons (PhPs) in van der Waals (vdW) bi-layers. We experimentally observe tunable topological transitions from open (hyperbolic) to closed (elliptic) dispersion contours in twisted bi-layered α-MoO3 at photonic magic angles, induced by polariton hybridization and robustly controlled by a topological quantity. At these transitions the bilayer dispersion flattens, exhibiting low-loss tunable polariton canalization and diffractionless propagation with resolution below λ0/40. Our findings extend twistronics and moiré physics to nanophotonics and polaritonics, with great potential for nano-imaging, nanoscale light propagation, energy transfer and quantum applications.
