Topological photonics has revolutionized our understanding of light propagation, providing a robust way to manipulate light. So far, most of studies in this field are focused on designing a static photonic structure. Developing a dynamic photonic topological platform to switch multiple topological functionalities at ultrafast speed is still a great challenge. Here we theoretically propose and experimentally demonstrate a reprogrammable plasmonic topological insulator, where the topological propagation route can be dynamically changed at nanosecond-level switching time, leading to an experimental demonstration of ultrafast multi-channel optical analog-digital converter. Due to the innovative use of electric switches to implement the programmability of plasmonic topological insulator, each unit cell can be encoded by dynamically controlling its digital plasmonic states while keeping its geometry and material parameters unchanged. Our reprogrammable topological plasmonic platform is fabricated by the printed circuit board technology, making it much more compatible with integrated photoelectric systems. Furthermore, due to its flexible programmability, many photonic topological functionalities can be integrated into this versatile topological platform.

拓扑光子学彻底改变了我们对光传播的理解，提供了一种操纵光的可靠方法。到目前为止，该领域的大多数研究都集中在设计静态光子结构。开发动态光子拓扑平台以超快的速度切换多种拓扑功能仍然是一个巨大的挑战。在这里，我们从理论上提出并通过实验演示了一种可重新编程的等离子体拓扑绝缘体，其中拓扑传播路径可以在纳秒级的切换时间动态改变，从而实现超快多通道光学模数转换器的实验演示。由于创新地使用电开关来实现等离子体拓扑绝缘体的可编程性，每个晶胞都可以通过动态控制其数字等离子体状态进行编码，同时保持其几何形状和材料参数不变。我们的可重编程拓扑等离子体平台采用印刷电路板技术制造，使其与集成光电系统更加兼容。此外，由于其灵活的可编程性，许多光子拓扑功能可以集成到这个多功能拓扑平台中。