Nanoimprinted topological laser in the visible

Nanoimprint lithography (NIL) is a widely used, high-throughput fabrication technique for photonic devices. However, its reliability is typically compromised by inevitable imperfections introduced during the demolding process. Topological photonics, which harnesses topologically non-trivial structures to support defect-robust photonic states, offers a promising solution to this limitation. Here, we demonstrate a topological laser fabricated via single-step nanoimprinting onto colloidal perovskite nanocrystals. This laser supports multiple higher-order topological corner states (HOTCS), with the topological protection provided by the structure effectively mitigating fabrication imperfections that typically arise during nanoimprinting. This robustness enables the reliable detection of these HOTCS, a feat that is particularly challenging to achieve within the visible spectrum. Overall, we established topological photonics as a viable pathway for enhancing the reliability of NIL-based manufacturing, providing a scalable and practical route for the mass production of topological lasers with low-index materials.