Materials exhibiting mechanoluminescence (ML) that directly convert mechanical stimuli into light hold significant potential for real-time stress sensing and intelligent photonic systems. However, most high-performance ML systems rely on complex multicomponent compounds that often suffer from limited intensity, stability, and scalability, largely due to poorly understood mechanisms. Herein, we report a simple Al₂O₃:Cr³⁺ oxide that exhibits unprecedented ML intensity, enabled by a well-defined mechanical-to-optical energy conversion process. The self-recoverable ML arises from stress-induced ionization of electrons from luminescence centers, followed by their recapture upon stress release. By precisely tuning the doping levels, annealing conditions, and heterojunction interfaces, Al₂O₃:Cr³⁺ phosphors achieved intense, reproducible, and thermally stable near-infrared emission. Notably, high-temperature …