标题： 具有空间可变可切换光-物质相互作用的二维莫尔超晶格中的梯度极化子表面 显示英文标题

标题： Gradient polaritonic surface with space-variant switchable light-matter interactions in 2D moire superlattices

摘要： 二维（2D）材料中的极化子为在纳米尺度上控制光提供了独特的机会。通过具有空间变化响应的梯度极化子表面来调节这些极化子，可以实现具有先进功能的多功能光-物质相互作用平台。然而，实验进展受到传统使用的人工纳米结构的光学损耗和较差的光限制的阻碍。在这里，我们展示了基于超晶格的自然梯度极化子表面，这些超晶格是由孤子局部结构变形构成的，在一个典型的莫尔系统——氮化硼上的扭曲双层石墨烯中。我们演示了局部极化子-孤子相互作用的开-关切换和连续调制，这是由于局部应变方向的变化对拓扑和传统孤子状态进行了显著修改所致。此外，我们揭示了这些结构在记录最小的占地面积内对极化子的近场轮廓、相位和传播方向进行空间修改的能力，从而实现了定向极化子的生成和电控开关。我们的研究结果为通过梯度莫尔超晶格实现光-物质相互作用的纳米级操控和空间极化子工程开辟了新的途径。 显示英文摘要

摘要： Polaritons in two-dimensional (2D) materials provide unique opportunities for controlling light at nanoscales. Tailoring these polaritons via gradient polaritonic surfaces with space-variant response can enable versatile light-matter interaction platforms with advanced functionalities. However, experimental progress has been hampered by the optical losses and poor light confinement of conventionally used artificial nanostructures. Here, we demonstrate natural gradient polaritonic surfaces based on superlattices of solitons-localized structural deformations-in a prototypical moire system, twisted bilayer graphene on boron nitride. We demonstrate on-off switching and continuous modulation of local polariton-soliton interactions, which results from marked modifications of topological and conventional soliton states through variation of local strain direction. Furthermore, we reveal the capability of these structures to spatially modify the near-field profile, phase, and propagation direction of polaritons in record-small footprints, enabling generation and electrical switching of directional polaritons. Our findings open up new avenues toward nanoscale manipulation of light-matter interactions and spatial polariton engineering through gradient moire superlattices.