Macroscopic Coherence and Vorticity in a Room-Temperature Polariton Condensate Confined in a Self-Assembled Perovskite Microcavity

High Resolution Image Download MS PowerPoint Slide Metal-halide perovskites have emerged as a novel platform for room-temperature exciton-polariton condensation owing to their strong light-matter coupling, large exciton binding energies, and compatibility with scalable fabrication methods. Unlike DBR-based and nanostructured systems, self-assembled CsPbBr 3 whispering-gallery-mode (WGM) microcavities provide an elegant architecture that naturally combines tight lateral photon confinement with optical gain. These microplatelets intrinsically host a disordered energy landscape, creating a regime in which confinement, gain, and disorder are inherently intertwined. Here, we report the observation of macroscopic coherence and quantized vortices in a room-temperature polariton condensate formed in such cavities. Although the system exhibits the standard signatures of a driven-dissipative condensate, including a nonlinear emission threshold, spectral narrowing, and interaction-induced blueshift, we go beyond these conventional indicators by directly resolving the spatial coherence and phase structure of the condensate. Interferometric measurements reveal extended phase coherence across the cavity, while fork-shaped dislocations in the interference fringes provide direct evidence of quantized vortices in the condensate wave function. These results demonstrate that structural disorder, rather than being detrimental, plays an active role in reshaping the effective cavity potential, inducing real-space fragmentation and stabilizing topological excitations in a lithography-free platform.