Damage growth characteristics on the exit surface of fused silica by the low-temporal coherence light irradiation.

The growth of fused silica surface damage poses a high risk in operating high-power laser devices, with complex physical mechanisms related not only to the wavelength, pulse width, fluence of incident pulse lasers, but also to initial damage size and material properties. With low-temporal coherence light (LTCL) increasingly applied in high-power laser-driven inertial confinement fusion (ICF), LTCL-induced damage growth has become a bottleneck limiting output power improvements. This paper analyzes LTCL damage growth characteristics and mechanisms on fused silica surfaces, obtaining its damage growth coefficient and threshold. By analyzing chemical composition variation, electric field of initial damage, and comparing the damage growth threshold of artificial initial damage, the mechanism of surface damage growth is investigated. This research provides reliable information for estimating fused silica lifetime in high-power LTCL devices and contributes to understanding LTCL properties.