Jin Feng, Mandal Subhaskar, Wang Xutong, Zhang Baile, Su Rui
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
Department of Physics, Indian Institute of Technology Bombay, Mumbai, India.
Nat Commun. 2025 Jul 1;16(1):6002. doi: 10.1038/s41467-025-61120-6.
Topologically nontrivial systems can be protected by band topology in momentum space, as seen in topological insulators and semimetals, or real-space topology, such as in lattice deformations known as topological disclinations (TDs). TDs, with inherent chiral symmetry, can support localized states pinned spectrally to the middle of the topological gap, preventing hybridization with bulk bands, and making them promising for topological lasers. Here, we experimentally realize a symmetric TD laser based on perovskite exciton-polariton lattices at room temperature. Protected by the chiral and point group symmetries of the lattice, the TD state emerges in the middle of the gap and at the core of the perovskite lattice. Under a non-resonant pulsed excitation, coherent polariton lasing occurs precisely at the TD state with a low threshold of 9.5 μJ/cm, as confirmed by momentum space and real space spectra measurements. This study not only introduces a class of symmetry-protected topological lasers, but also expands the landscape for exploring exciton-polariton light-matter interactions with novel topological structures.
拓扑非平凡系统可以在动量空间中受到能带拓扑的保护，如拓扑绝缘体和半金属中所见，或者在实空间拓扑中受到保护，例如在被称为拓扑位错（TDs）的晶格变形中。具有固有手性对称性的TDs可以支持局域态，这些局域态在光谱上被钉扎在拓扑能隙的中间，防止与体带发生杂化，这使得它们在拓扑激光器方面具有潜力。在这里，我们在室温下通过基于钙钛矿激子-极化子晶格实验实现了一种对称TD激光器。受晶格的手性和点群对称性保护，TD态出现在能隙中间和钙钛矿晶格的核心处。在非共振脉冲激发下，通过动量空间和实空间光谱测量证实，相干极化子激光恰好发生在TD态，阈值低至9.5 μJ/cm²。这项研究不仅引入了一类对称保护的拓扑激光器，还拓宽了探索具有新型拓扑结构的激子-极化子光-物质相互作用的领域。
