Kumar Abhishek, Tan Yi Ji, Navaratna Nikhil, Gupta Manoj, Pitchappa Prakash, Singh Ranjan
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, Singapore, 639798, Singapore.
Nat Commun. 2024 Jan 31;15(1):926. doi: 10.1038/s41467-024-45175-5.
Topological slow light exhibits potential to achieve stopped light by virtue of its widely known robust and non-reciprocal behaviours. Conventional approach for achieving topological slow light often involves flat-band engineering without disentangling the underlying physical mechanism. Here, we unveil the presence of counter-propagating waves within valley kink states as the distinctive hallmark of the slow light topological photonic waveguides. These counter-propagating waves, supported by topological vortices along glide-symmetric interface, provide significant flexibility for controlling the slowness of light. We tune the group velocity of light by changing the spatial separation between vortices adjacent to the glide-symmetric interface. We also dynamically control the group delay by introducing a non-Hermitian defect using photoexcitation to adjust the relative strength of the counter-propagating waves. This study introduces active slow light topological photonic device on a silicon chip, opening new horizons for topological photon transport through defects, topological light-matter interactions, nonlinear topological photonics, and topological quantum photonics.
拓扑慢光凭借其广为人知的稳健和非互易特性，展现出实现光停止的潜力。实现拓扑慢光的传统方法通常涉及平带工程，而未厘清其潜在的物理机制。在此，我们揭示了谷扭结态中反向传播波的存在，这是慢光拓扑光子波导的独特标志。这些由沿滑移对称界面的拓扑涡旋所支持的反向传播波，为控制光的慢度提供了显著的灵活性。我们通过改变与滑移对称界面相邻的涡旋之间的空间间距来调节光的群速度。我们还通过光激发引入非厄米缺陷来动态控制群延迟，以调整反向传播波的相对强度。本研究在硅芯片上引入了有源慢光拓扑光子器件，为通过缺陷的拓扑光子传输、拓扑光与物质相互作用、非线性拓扑光子学以及拓扑量子光子学开辟了新视野。
