复杂通道中的拓扑时空波
Topological space-time waves in complex channels
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中文总结 AI 辅助
研究人员通过对称破缺超表面的共振响应一步生成拓扑时空光束，可直接观察其在任意通道中的动力学，首次实现时空波的无串扰传输，为其在稳健通信等领域的应用提供了新工具。
中文摘要 AI 辅助
时空结构化光已成为探索波系统基础物理的强大平台，同时催生了从时空涡旋到环形光脉冲等多种奇异光形式。然而它们的产生仍受限于复杂的光学系统，且由于色散与衍射的相互作用，再加上缺乏合适的探测工具，直接观察其在任意通道中的演化仍十分困难。本文中，我们通过对称破缺超表面的共振响应一步生成拓扑时空光束，在单一微波场中混合空间、时间和偏振自由度。我们在微波领域的实现使我们能够直接观察其在任意通道（从自由空间到复杂随机介质）中的动力学，显示在基础自由度被扰乱时拓扑仍保持不变。我们利用这种控制方法首次展示了解扰时空特性以实现时空波的无串扰传输。我们的工作推进了时空波的物理研究，引入了一套新的生成与控制工具，并为其在实际场景中的应用提供了令人兴奋的路线图，例如用于通过噪声通道的稳健通信。
英文摘要
Structured light in space and time has become a powerful playground in which to explore the fundamental physics of wave systems, while simultaneously introducing new exotic forms of light, from spatio-temporal vortices to toroidal pulses of light. Yet their creation remains restricted by complex optical systems while directly observing their evolution in arbitrary channels remains elusive, complicated by the interplay of dispersion and diffraction and exacerbated by the lack of suitable detection tools. Here we create topological space-time beams in a single step by a resonant response of a symmetry-broken metasurface, mixing spatial, temporal and polarisation degrees of freedom in a single microwave field. Our realisation in the microwave regime allows us to directly observe their dynamics in arbitrary channels, from free-space to complex random media, showing the preservation of topology while the foundational degrees of freedom are scrambled. We use our control to show how to unscramble the space-time properties for the first crosstalk-free transmission of space-time waves. Our work advances the physics of space-time waves, introduces a new toolkit for their creation and control, and offers an exciting roadmap to their exploitation in real-world scenarios, e.g., for robust communications through noisy channels.
