Exciton polariton condensation from bound states in the continuum at room temperature

Exciton-polaritons (polaritons) resulting from the strong exciton-photon interaction stimulate the development of novel low-threshold coherent light sources to meet increasing energy demands of optical communications. 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 polariton accumulation. However, BIC polariton condensation has been limited to cryogenic temperatures due to small exciton binding energies in conventional material platforms. Here, we demonstrate room-temperature BIC polariton condensation in perovskite photonic crystal lattices. BIC polariton condensation occurs near the saddle point of the polariton dispersion, generating directional vortex-beam emission with long-range coherence. We also explore switching among miniaturized BIC polariton modes through effective polariton-polariton scattering. Our work paves the way for practical implementation of BIC polariton condensates for integrated photonic and topological circuits.

Xianxin Wu, Shuai Zhang, Jiepeng Song, Xinyi Deng, Wenna Du, Xin Zeng, Yuyang Zhang, Zhiyong Zhang, Yuzhong Chen, Yubin Wang, Chuanxiu Jiang, Yangguang Zhong, Bo Wu, Zhuoya Zhu, Yin Liang, Qing Zhang, Qihua Xiong, Xinfeng Liu