Low-threshold colloidal quantum dot polariton lasing via a strong coupling microcavity at room temperature†

Abstract

Colloidal quantum dots (CQDs) are excellent optical gain media that can be synthesized through low-cost and easily controlled techniques, holding significant promise for applications in semiconductor laser devices. In this study, we demonstrated polariton coherent lasing based on a CdSe-based CQD microcavity device at room-temperature (RT) for the first time. The dispersion behaviors of CQD polaritons with different excitation powers were comprehensively analyzed using angle-resolved spectroscopy techniques. The lasing behavior at a threshold of 49 μJ cm⁻² and the energy blue-shift were well aligned with the typical characteristics of robust polariton Bose–Einstein condensation (BEC) theory. Moreover, the linewidth of the polariton lasing peak was narrowed down to 0.65 nm at 1.13P_th. Additionally, the polarization characteristics and temporal dynamics of the CQD-microcavity polariton lasing were discussed. It was noted that the lifetime of CQD polaritons during condensation was reduced from 1.3 ns (0.8P_th) to 68 ps (1.6P_th). Our results provide valuable insights into the strong coupling, low-threshold CQD microcavity laser at RT and promote its further practical application.