Exciton–polaritons (polaritons) resulting from the strong exciton–photon interaction stimulates the development of novel low-threshold coherent light sources to circumvent the ever-increasing energy demands of optical communications^1,2,3. Polaritons from bound states in the continuum (BICs) are promising for Bose–Einstein condensation owing to their theoretically infinite quality factors, which provide prolonged lifetimes and benefit the polariton accumulations^4,5,6,7. However, BIC polariton condensation remains limited to cryogenic temperatures ascribed to the small exciton binding energies of conventional material platforms. Herein, we demonstrated room-temperature BIC polariton condensation in perovskite photonic crystal lattices. BIC polariton condensation was demonstrated at the vicinity of the saddle point of polariton dispersion that generates directional vortex beam emission with long-range coherence. We also explore the peculiar switching effect among the miniaturized BIC polariton modes through effective polariton−polariton scattering. Our work paves the way for the practical implementation of BIC polariton condensates for integrated photonic and topological circuits.

由强激子-光子相互作用产生的激子-极化子（极化子）刺激了新型低阈值相干光源的发展，以避免光通信不断增长的能源需求^1,2,3 。来自连续体束缚态 (BIC) 的极化子由于理论上无限的质量因子而有望用于玻色-爱因斯坦凝聚，从而延长寿命并有利于极化子的积累^4,5,6,7 。然而，由于传统材料平台的激子结合能较小，BIC 极化子凝聚仍然限于低温。在此，我们证明了钙钛矿光子晶格中的室温 BIC 极化子凝聚。在极化子色散鞍点附近证明了 BIC 极化子凝聚，产生具有长程相干性的定向涡旋光束发射。我们还通过有效的极化子-极化子散射探索了小型化 BIC 极化子模式之间的特殊切换效应。我们的工作为集成光子和拓扑电路的 BIC 极化子凝聚体的实际应用铺平了道路。