Chiral superconductivity — a long-sought quantum phase with potential applications in quantum technologies — has eluded definitive microscopic confirmation for decades. While several candidate materials exhibit signatures of time-reversal symmetry breaking, such evidence alone does not prove chiral Cooper pairing.

Using quasiparticle interference imaging in a structurally simple, engineered tin-on-silicon platform, we identified a robust and unambiguous microscopic fingerprint of chiral Cooper pairing. The observed interference patterns around symmetry-preserving atomic defects match theoretical simulations without parameter finetuning.

This work provides the first definitive microscopic identification of chiral superconductivity in a clean materials platform, establishing that chiral Cooper pairing is a physically realizable and experimentally accessible quantum phase. Beyond fundamental discovery, the ability to microscopically diagnose chiral pairing symmetries opens new pathways for designing and verifying quantum materials for next-generation technologies.