Surface defects on fused silica optics significantly limit their laser-induced damage resistance under ultraviolet pulsed laser irradiation, yet quantitative correlations between defect parameters and damage thresholds remain scarce. This study is the first to perform multimodal detection and correlation analysis of laser-induced damage initiated at real defects on fused silica. Scratches were characterized by scattered light intensity, width and fluorescence intensity, and correlated with the damage-onset fluence (DOF). Results show trailing indent scratches (1.9–8.8 μm wide) have DOFs of 1.27–13.2 J/cm2, while plastic continuous scratches (0.4–5.8 μm wide) exhibit higher DOFs of 12.3– 22.0 J/cm2. Fluorescence intensity strongly negatively correlates with DOF (p < 0.001), as do scratch width and fluorescence intensity at α = 0.01 (p < 0.01). These findings establish scratch width and fluorescence intensity as quantitative damage precursors, advancing surface quality assessment for high-energy laser optics.
