Su Rui, Ghosh Sanjib, Liew Timothy C H, Xiong Qihua
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
MajuLab, International Joint Research Unit UMI 3654, CNRS, Université Côte d'Azur, Sorbonne Université, National University of Singapore, Nanyang Technological University, Singapore 637371, Singapore.
Sci Adv. 2021 May 21;7(21). doi: 10.1126/sciadv.abf8049. Print 2021 May.
Strong light-matter interaction enriches topological photonics by dressing light with matter, which provides the possibility to realize active nonlinear topological devices with immunity to defects. Topological exciton polaritons-half-light, half-matter quasiparticles with giant optical nonlinearity-represent a unique platform for active topological photonics. Previous demonstrations of exciton polariton topological insulators demand cryogenic temperatures, and their topological properties are usually fixed. Here, we experimentally demonstrate a room temperature exciton polariton topological insulator in a perovskite zigzag lattice. Polarization serves as a degree of freedom to switch between distinct topological phases, and the topologically nontrivial polariton edge states persist in the presence of onsite energy perturbations, showing strong immunity to disorder. We further demonstrate exciton polariton condensation into the topological edge states under optical pumping. These results provide an ideal platform for realizing active topological polaritonic devices working at ambient conditions, which can find important applications in topological lasers, optical modulation, and switching.
强光与物质相互作用通过用物质修饰光来丰富拓扑光子学，这为实现对缺陷具有免疫能力的有源非线性拓扑器件提供了可能性。拓扑激子极化激元——具有巨大光学非线性的半光半物质准粒子——代表了有源拓扑光子学的一个独特平台。先前对激子极化激元拓扑绝缘体的演示需要低温，并且它们的拓扑性质通常是固定的。在此，我们通过实验证明了在钙钛矿锯齿形晶格中的室温激子极化激元拓扑绝缘体。极化作为一个自由度在不同的拓扑相之间切换，并且拓扑非平凡的极化激元边缘态在存在在位能量微扰的情况下仍然存在，表现出对无序的强免疫性。我们进一步证明了在光泵浦下激子极化激元凝聚到拓扑边缘态中。这些结果为实现工作在环境条件下的有源拓扑极化激元器件提供了一个理想平台，其可在拓扑激光器、光调制和开关中找到重要应用。
