Laser-induced damage growth of large-aperture fused silica optics under high-fluence 351 nm laser irradiation

Abstract Laser-induced damage (LID) of fused-silica optics is a key factor limiting the output energy of high-power laser facility. In this paper, we study the LID growth of a large-aperture fused silica wedged focus lens (WFL) and vacuum window (VW) at high-fluence 351 nm. Results show the damage sites number on both optics increases gradually with shots first, then tends to stabilize at the subsequent shots. Besides, the VW has much more damage sites and the damage size grows faster than that on the WFL. According to the damage morphology and growth behavior, the damage sites are mainly ascribed to the initial defects on surfaces. And the fluence variation may be responsible for their damage performance differences.