Mechanisms of the sharp decrease of the LIDT from the plastic surface defect to the brittle surface defect on optical surface

•A reciprocal relationship between the highest photoluminescence intensity (HPI) and the laser-induced damage threshold (LIDT) of the surface-defect zone is constructed for the first time.•The physical mechanism of the sharp decrease of the LIDT from plastic to brittle surface defects is revealed for the first time.•The slight increase of the HPI would lead to a sharp decrease of the LIDT from plastic to brittle surface defects.•E’-Center and STE point defects would increase sharply from plastic to brittle surface defects, causing a sharp increase of HPI.